Chapter 1 An Introduction to the Human Body

What Is Anatomy and Physiology?

• Anatomy: – The study of the structure and shape of the body and the relationships among structures • Physiology: – The study of the functions of the body parts.

1 Anatomy Subdivisions • Surface anatomy: – Study morphology and markings on the surface of the body • Gross anatomy: – Study structures without using microscope • Systemic anatomy: – Study structure of specific system, e.g. nervous system • Regional anatomy: – Study specific region of the body, e.g. head, chest

Anatomy Subdivisions • Radiographic anatomy: – Study the structures of the body using x-ray • Developmental biology: – Study the development from fertilized egg to adult • Embryology: – Study the development from fertilized egg through the eighth week in utero

2 Anatomy Subdivisions

• Histology: – Study of the structure of tissues using a microscope • Cytology: – Study chemical and microscopic study of cell structure • Pathology: – Study gross or microscopic structural changes

Physiology Subdivisions • Cell physiology: – Study the functions of cells • Pathophysiology: – Study the functional changes associated with disease and aging • Exercise physiology: – Study changes during muscular activity • Neurophysiology: – Study functional characteristics of nerve cells

3 Physiology Subdivisions • Endocrinology: – Study hormones and how they control the body functions • Cardiovascular: – Study function of the heart and blood vessels • Immunology: – Study body defense mechanism • Respiratory physiology: – Study function of air passageways and lungs • Renal physiology: – Study functions of the kidneys

Hierarchy of Complexity

• structural levels: – chemical, cellular, tissue, organ, system, organism • Chemical level: – Smallest components, atoms and molecules – Essential atoms to maintain life: C, H, O, N, Ca, P, Ca, S – Atoms make molecules: proteins, carbohydrates, fat, vitamins, etc. • Cellular level: – Molecules combine to form cells that vary in size, shape, and function – Cells are the basic structural and functional units of organisms e.g. muscle, nerve, blood cells – Cells contain organelles

4 Levels of Structural Organization

3. Tissue level: – Group of similar cells that have common function – There are 4 basic tissue types: • epithelial, muscle, connective, nervous tissue. 4. Organ level: – Two or more different types of tissue make an organ that have a specific function and shape – Example: heart, lung, brain…etc.

Levels of Structural Organization

5. System level (organ system): – Group of organs cooperate to a accomplish a common purpose • 11 organ system: Integumentary, Skeletal, Muscular, nervous, Endocrine, Cardiovascular, lymphatic, Respiratory, digestive, urinary, reproductive 6. Organismic level: – One living individual – All body parts functioning together

5 Levels of Structural Organization

Anatomical position

• The subject erect and facing the observer • The head level, and eyes facing forward. • The feet flat on the floor and forward • The arms placed at the sides with palms turned forward

6 Superior (cranial or Toward the head or above The nose is Superior to the Cephalad) mouth Inferior Toward the lower part of The mouth is inferior to the (Caudal) the body nose Anterior (ventral) Toward the front of the Breastbone anterior to the body spine Posterior Toward the back of the The heart posterior to the (dorsal) body breastbone Medial Toward the midline of the Breastbone medial to the body nipples Lateral Away from the midline of The nipples lateral to the the body breastbone Proximal Close to the origin Elbow is proximal to the wrist Distal Away from the origin Knee is distal to thigh Superficial Toward the body surface Skin is superficial the skeleton Deep Away from the body Skeleton are deep to the skin surface; more internal

Cranial Proximal Anterior

Lateral

7 Planes and Sections

• Planes: – Imaginary flat surfaces pass through body parts. • Section: – An actual cut or slice to reveal internal anatomy

Planes and Sections • Sagittal plane: – Vertical plane divides the body into right and left – Midsagittal plane: Divides the body into equal right and left halves – Parasagittal: Divides the body into two not equal halves.

8 Planes and Sections • Frontal (coronal) plane: – Divides the body into anterior and posterior • Transverse plane: – Divides the body into superior and inferior • Oblique plane: – passes through the body or an organ at an angle between the transverse plane and sagittal or frontal plane.

Body Cavities

• Cavities are confined spaces within separated by muscles, bones, or ligaments • Cavities contain internal organs • Two main cavities: dorsal and ventral

9 Body Cavities

• Dorsal cavity: – located near the back and subdivided into: 1. Cranial cavity contains the brain 2. Vertebral canal contains the spinal cord

Body Cavities

• Ventral cavity – located near the front and subdivided by the diaphragm into – Thoracic cavity contains lungs, heart, esophagus, trachea, thymus, and large blood vessels – Abdomenopelvic cavity contains stomach, spleen, liver, gallbladder, small intestine, large intestine, urinary bladder, portion of large intestine, internal organs of reproductive system.

10 Thoracic and Abdominal Cavity Membranes

• Membranes cover the viscera and line the walls of the thorax and abdomen • Pleura: covers the lungs and lines chest wall • Pericardium: covers the surface of the heart

Thoracic and Abdominal Cavity Membranes • Peritoneum: – covers the abdominal viscera and lines the abdominal wall • Retroperitoneal: – Located behind the parietal peritoneum such as kidneys, adrenal glands, pancreas

11 Abdominopelvic Regions

• 4 lines divide the abdominal cavity into 9 regions • 2 horizontal lines – Subcostal line drawn just inferior to rib 10 – Transtrabecular line drawn inferior to the tops of the hip bones • 2 vertical lines: – left and right midclavicular lines drawn through the mid point of the clavicles medial to the nipple

Nine Abdominal Regions

12 Quadrants • A vertical line and a horizontal line pass through the umbilicus and divide the abdominopelvic cavity into 4 quadrants – RUQ, RLQ, LUQ, LLQ

Clinical quadrants of Abdomen • Right upper quadrant-RUQ – Liver (main) – Gallbladder – Head of pancreas – Colon – Right kidney • Left upper quadrant- LUQ – Liver (tip) – Spleen – Left kidney – Stomach – Colon

13 Lower quadrants of Abdomen • Right lower quadrant- RLQ – Colon, ascending – Small intestines – Right Ureter – Appendix – Bladder • Left lower quadrant-LLQ – Sigmoid colon – Left Ureter – Small intestines – Aorta – Bladder

14 Chapter 2 Chemistry

• Synthesis Reactions also called Anabolism – A + B  AB – Reactants: A, B – Product: AB – Example: amino acids combine to make protein • Decomposition Reaction also called Catabolism – AB  A + B – Example: Digestion of food

15 Chemical Compounds

• Inorganic compounds: – Usually small simple structure – Lack Carbon – Example: water, salt, acids, base…etc. • Organic compounds: – Always contain carbon – Example: carbohydrates, lipids, proteins, Vitamins, ATP.

Carbohydrates

• Sugars, starch, glycogen, cellulose • Used as a Source of energy or as a structural units to make compound such as DNA. • Can be stored as glycogen in liver and skeletal muscle • Divided into three groups – Monosaccharides: Glucose, Fructose, Galactose. – Disaccharides: 2 monosaccharides • Glucose + Fructose Sucrose + H2O (dehydration). • Glucose + Galactose  Lactose – Polysaccharides: Contain 10 or more monosaccharides such as glycogen.

16 Lipids • Many Types: – Triglycerides, Phospholipids, Steroids, Fatty acids, Fat soluble vitamins, Lipoproteins • Triglycerides: – Saturated fat (saturated with H atoms) • Solid at room temperature • Mostly in animals, also in few plant product (Coconut oil). • Butter, margarine, grease – Unsaturated fat • liquid in room temperature • Olive oil, vegetable oil

Proteins • Made from amino acids. • Bond between amino acids is called peptide bond

17 Cells & Tissues

Anatomy of The Cell

• Cells are the building block of living things such as Plants, animals • All cells have three main regions 1. Nucleus 2. Plasma membrane, also called cell membrane 3. Cytoplasm

18 Plasma Membrane

• Flexible, fragile outer membrane. • Two layers of lipid separate intracellular components from extra cellular environment • Allows passage of several types of lipid soluble molecules • Acts as a barrier to the entry or exit of polar substances • Has a dynamic role in many cellular activities • Plays a key role in communication.

• Site of most cellular activities cytoplasm • Has three major elements • Cytosol: – Semitransparent fluid – Made of water and solutes and suspends other elements • Organelles – Means little organs • Inclusions: – Temporary structures in the cytoplasm, may or may not be present

19 • Specialized structures have characteristic Organelles appearance and specific roles in cellular growth, maintenance, reproduction • Each organelle has set of enzymes to carry out specific reactions

Organelles; Mitochondria • Main site to generate ATP • Active cells have large number of mitochondria

20 Organelles; Ribosomes

• The site of making proteins • Can be free or attached to endoplasmic reticulum

Organelles; Endoplasmic Reticulum

• Membrane-enclosed channels called cisterns or cisternae • The channels carry substances from one part of the cell to another • Two types: – Rough ER: Studded with ribosomes, synthesize proteins – Smooth ER: Has no ribosomes, synthesize steroids, phospholipids, fatty acid

21 Organelles; Golgi Complex

• Located near the nucleus • Consist of 3-20 curved cisternae • Modifies, sorts, and packages proteins for transport to different destinations.

Organelles; Lysosomes

• Membrane enclosed vesicles contain digestive enzymes that break down a variety of molecules; bacteria, harmful substances …etc • Abundant in WBC • Rupture of lysosomes result in self-digestion of the cell

22 Organelles; Cytoskeleton

• Complex internal network of filamentous proteins in the cytoplasm • Provides structural framework for the cell • Responsible for movement of a whole cell, movement of organelles, and some chemicals within the cell

Organelles; Centrioles

• A pair of cylindrical structure perpendicular to each other • Lie close to the nucleus • Involved in cell division

23 Type of Tissues

1. Connective tissue 2. Muscle tissue 3. Nerve tissue: 4. Epithelial tissue:

Type of Tissues

1. Epithelial tissue: – Covers body surfaces; Skin – Lines hollow organs, body cavities and ducts – Forms glands e.g. thyroid gland sweat glands

24 Connective Tissues

• Protect and support body and organs • Store fat • Connect body parts • Connective tissue do not occur on the body surface • Highly vascular, except cartilage, tendons and ligaments • Have nerve supply, except for cartilage • Connective tissue consist of matrix and cells:

Types of Connective Tissue • Areolar connective tissue – Widely distributed, – cushions and protects organs – Consist of loose fibers and many cells • Adipose tissue: – Stores Triglycerides – Protects organs (kidney, eye), reduces heat loss, energies reserve

25 Types of Connective Tissue • Reticular connective tissue: – Fine fibers make framework organs such as liver, spleen and lymph nodes • Dense connective tissue – A lot of fibers give strength to the structure

Types of Connective Tissue

• Elastic connective tissue – confer elasticity to organs- lungs, arteries • Bone Tissue: Two types – Spongy: contains red bone marrow – Compact bone: solid

26 1. Hyaline cartilage: – Most abundant and weakest – Supports structures of larynx, ribs, end of bones ( joints) 2. Fibrocartilage: – The strongest cartilage – Found in Intervertebral disc. 3. Elastic cartilage: – Provides strength and elasticity – Found in the external ear

Muscle Tissue

1. Skeletal: – Usually attached to bones or skin; Voluntary muscles – maintain posture, generate heat 2. Smooth – Located in the wall of internal organs ; blood vessels, Involuntary 3. Cardiac muscle: – The heart muscle, involuntary

27 Nervous Tissue

• Detects changes inside and outside the body • Generates impulses • Two types of cells – Neurons – Neuoraglia:

Tissue repair (wound healing)

• Two major ways to heal the wounds • Regeneration: – Replacement of destroyed tissue by the same kind of cells • Fibrosis: – Repair by dense fibrous connective tissue  scar tissue • Clean cuts heel faster than ragged tears.

28 Cells and Aging

• Geriatrics: – A branch of medicine that deals with the medical problems and care of elderly person

Integumentary System

29 • Definition: – Skin and its Integumentary accessory structures – hair, nails, sweat, System and oil glands. • Largest organ in the body • Has largest surface area and weight, covers two square meters in adults • Have 2 main parts: 1. Epidermis: superficial 2. Dermis: deep.

Function of the Skin • Thermoregulation: – Heat loss : activating sweat glands and allowing blood to flush into skin capillary bed – Heat retention: blood not flushing into skin capillary bed • Protection: – Keratin protects us from microbes, abrasions, heat, chemicals – Acidic perspiration retarded growth of microbes – Melanin provide protection against UV light – Macrophages in the dermis phagocytize bacteria, viruses • Sensations: – touch, pressure, vibration, tickling, temperature, pain • Excretion: – Water, small amount salts, CO2, ammonia, urea • Absorption: – Lipid, drugs, toxic materials (acetone) • Synthesis of vitamin D

30 Epidermis

• Layers from superficial to deep: 1. Stratum corneum: – contain dead keratinocytes that shed and replaced by cells from deeper strata – Callus: abnormal thickening of the stratum corneum 2. Stratum Lucidum: – found in thick hairless skin only; palms and soles 3. Stratum Granulosum 4. Stratum Spinosum 5. Stratum Basale: – Deepest layer – The cells divide to produce new keratinocytes; daughter cells are pushed upward toward the surface

Dermis

• Deeper layer • Vary in thickness (feet, eyelids) • Strong and stretchy; helps hold the body together • Contains fibers, cells, blood vessels, nerves, glands, hair follicle

31 Skin Color

• Melanin: – color vary from pale yellow to tan to black – Exposure to UV increase melanin production – Number of Melanocytes is about the same in all people • Carotene: – Yellow-orange pigment, a precursor of vitamin A. • Hemoglobin: – Red color

Imbalance

• Cyanosis: blue • Erythema: redness • Pallor: blanching • Jaundice: yellow cast • Bruises: black and blue marks

32 • Thin skin ( hairy): – Covers all all parts of the body, except palms, palms surfaces of the digit, and Skin Types soles – Contains hair follicles, arector pili and sebaceous gland • Thick skin: – Covers palms, palmer surface of fingers, and soles – Thick epidermis – Lack hair follicles, arrector pili muscle, and sebaceous glands. – Have more sweat glands and sensory receptors.

Accessory structures of the skin

• Hair and hair follicles • Skin gland • Nails

33 • Sebaceous glands – Found in all skin except Skin glands on the palms and soles – Secrete sebum which coats hair surface, prevents excessive evaporation from skin – More active in adolescence – Acne: active infection of sebaceous glands • Sweat glands – Secret sweat; – Sweat function: inhibit bacterial growth, regulates body temperature, eliminating waste

Anatomy of Hair • Shaft: – Superior portion of the hair projects from the surface of the skin • Root: – Deeper to the shaft penetrates into the dermis

34 Anatomy of Hair

• Hair follicle. – Surrounds the hair root • Hair bulb – Involved in hair growth • Arrector pili. – Smooth muscle extends from the dermis to the side of the hair follicle – Contraction cause goose bumps

Hair color

• Color is due to the amount and type of melanin in its keratinized cells • Dark colored hair contains mostly true melanin • Blond and red hair contain variants of melanin with more iron and sulfur • Gray hair results from decline in tyrosinase • White hair result from air bubbles in the medullary shaft

35 Functions of Hair

• Protection from sun ray • Decrease heat loss from the scalp • Protect from foreign particles: – Eyebrows, eyelashes, hair in the nostrils, external ear canal • Sensing light touch

Nails

• packed keratinized epidermal cells • Nail body: visible attached portion • Free edge • Nail root: embedded in skin. • Nail folds: nail borders overlapped by skin folds • Cuticle: thick proximal nail fold • Nail bed: epidermis beneath the nail • Lunula: the white crescent • Function: grasp, protect digits, scratching

36 Burns

• tissue damage and cell death caused by intense heat, electricity, UV radiation (sunburn), chemicals (acids) • Degree of Burns – First degree: • Epidermal damage only • red and swollen • Not serious, heals within two to three days, can be painfull • Example: sunburn

Burns

• Second degree – Injury to epidermis and upper region of dermis – Red, painful skin, cause blisters – No permanent scars • Third degree – Destroy the entire thickness of the skin – Not painful; black area – Regeneration is not possible. Cause scars

37 First & second degree burns

Third degree burns

38 Skin Cancer

• Basal cell carcinoma – Most common – Least malignant; slow- growing, rarely metastasize to other tissues – Surgically removed • Squamous cell carcinoma – Grows rapidly and metastasize to adjacent lymph nods – Removed surgically or radiation therapy, good prognosis

Skin Cancer

• Malignant Melanoma – Cancer of melanocytes – Metastasize rapidly to surrounding lymph and blood vessels – Poor prognosis

39 Risk factors for skin cancer

• Overexposure to UV • Frequent skin irritation (infections, chemicals, physical trauma) • Skin type: lighter skin = higher risk • Family history: Genetics plays some role • Age: older = longer exposure. • Compromised immune systems means greater risk

ABCDs rule for recognizing melanoma

40 Skeletal System

Division of the Skeletal System

• Axial skeleton – 80 bones – Consist of bones arranged along the axis • Appendicular skeleton – 126 bones – The bones of the limb and girdle

41 Functions of Bone

• Support and protect organs (cranium , vertebrae, rib cage) • Help movement; skeletal muscles contract and pull the bones which result in movement • Release and store minerals ( Ca, P) • Red bone marrow produce blood cells and platelets • Store TG • Red bone marrow is involved in homopoiesis. •

Bone cells

Osteoblasts Osteoclasts Osteocytes

42 Classification of bones

• Two types of bone tissue: 1. Compact bone: • Dense, smooth, and homogeneous 2. Spongy bone: • trabiculae ( needle like pieces ) and lots of open spaces • Bones sizes and shapes 1. Long bone. 4. Short bone. 2. Flat Bones. 5. Irregular Bones. 3. Sesamoid Bones

Long Bones.

• Longer than wide • Consist of: – Shaft contains compact bone – Heads at both ends contain spongy bone • All limb bones are long bones except the wrist and ankle bones • Example femur, tibia, fibula…etc.

43 Short Bones.

• Cube – shaped. • nearly equal in length and width. • Consist of spongy bone covered by a thin layer of compact bone Short Bone • Example: bones of the wrist and the ankle

Flat Bones.

• Thin, flat and usually curved • composed of 2 parallel plates of compact bone enclosing a spongy bone • Example: most cranial bones, ribs, sternum.

44 Irregular Bones.

• Complex shape. • Contain various amount of compact and sponge bones. • Example: vertebrae, hip. Irregular Bones.

Long bone structure

• Compact bone • Spongy bone • Epiphysis – Articular Cartilage • Diaphysis – Medullary cavity • Matphysis

45 Factors Affecting Bone Growth

• Adequate dietary intake – calcium, phosphorous, fluoride, magnesium, iron, manganese, Vitamins D, C, K, B12, A • Rickets: – the bone fails to calcify  soft bone  bowing – Lack of Ca, or vit D

Cranial and Facial Bones

46 Cranial and Facial Bones

Cranial Bones

47 Nasal Septum

• Divide the nasal cavity into left and right sides • Consist of three bones and cartilage

Sutures 1. Coronal: unites frontal bone and both parietal bones 2. Sagittal: unites the two parietal bones 3. Lambdoid: unites both parietal bones to the occipital bone 4. Squamous: unites the parietal and temporal bones on the lateral aspect on each side of the skull

48 Fontanels 1. Anterior fontanel: between parietal bones and frontal bones 2. Posterior fontanel: between parietal bones and occipital bone 3. Two anterolateral: located laterally between frontal, parietal, temporal, and sphenoid bones 4. Two posterolateral: located laterally between parietal, occipital, and temporal bones.

Hyoid Bone • Single bone does not articulate with any other bone • Suspended in the anterior neck between mandible and larynx • Consist of – Body – Lesser horns – Greater horns

49 Vertebral Column • Flexible, can move forward, backward, sideways, and rotate • Encloses the spinal cord • Supports the head • Provides point of attachment for ribs, pelvic girdle, muscles of the back • Contains 26 vertebrae: – 7 cervical – 12 thoracic – 5 lumber – 1 sacrum – 1 coccyx.

• formed by Thorax, Thorcic Cage sternum, coastal cartilages, ribs, bodies of the thoracic vertebrae. • Flattened from front to back • narrower superiorly and broader inferiorly • Protects organs in chest • Provides support for the bones of the shoulder girdle

50 Pectoral (Shoulder) Girdle

• Two pectoral girdle. • Each girdle attach the upper limbs to axial skeleton. • Consist of two bones: – Clavical anteriorly. – Scapula posteriorly.

Upper Limb

• Consist of: – Humerus – Ulna – radius – 8- carpals – 5- metacarpals – 14 phalanges

51 Carpals

• 8 carpals arranged in two transverse rows; 4 bones each

Pelvic (Hip) Girdle • Two hip bones • Bony pelvis: – pubic symphysis, sacrum, hip bones • Hip bone consist of 3 bones – Ilium: Superior – Pubis: Inferior and anterior – Ischium: inferior and posterior

52 Lower Limb

• Each lower limb consist of: 1. Femur 2. Patella 3. Tibia 4. fibula 5. 7 tarsals 6. 5 metatarsals 7. 14 phalanges

Tarsal Bones

• Calcaneus: • Cuboid bone • Navicular • cuneiform bones • Talus bone • Intertarsal joints:

53 Bone Fracture • Simple or closed fracture: – Does not break the skin • Open (compound) fracture: – Broken ends protrude through the skin

Exercise and Bone Tissue

• Increase mineral salts deposition and production of collagen fibers – athletes bones are thicker and stronger • Without mechanical stress – Affect mineralization and decreased number of collagen fibers

54 Muscle System

Muscles • Come from the Latin word mus ( little mouse) because flexing muscles look like mice scurrying beneath the skin • Muscle characteristics – All muscles contract; essential for all body movements – All have the prefixes- myo-, mys- , or sarco- Three types of Muscle Tissue – Skeletal muscles – Smooth Muscles – Cardiac muscle

55 Function of Muscle Tissue 1. Producing body movement: – Walking, nodding …etc. 2. Stabilizing body positions – Postural muscle - neck muscle…etc. – Stabilizing joints - maintain body position. 3. Storing and moving substances within the body: – Intestine, Heart, Arteries 4. Generating heat: – Contraction  heat  thermogenesis.

Neuromuscular Junction

• The region of contact between the somatic motor neuron and the membrane (sarcolemma) of a muscle cell

56 Muscle Fatigue

• Inability of the muscle to contract even though it is still being stimulated – Lack oxygen  lactic acid accumulate – Decrease ATP supply

• Is a small amount of tension in the muscle Muscle tone due to weak, involuntary contraction • Does not produced movement • To sustain muscle tone, small groups of motor units are alternately active and inactive in a shifting pattern ( GI, back, neck, vessels • In flaccid muscle, the tone is lost

57 Coordination with a muscle groups • Opposing: – Prime mover (agonists): causing a particular movement. – Antagonist: opposes or reverse a movement – If the prime mover active, the antagonist relaxes • Synergists: – Help the prime movers

Effect of exercise on muscle

• Exercise – increases muscle size and strength – immobilization leads to muscle weakness • Aerobic exercise – Increases blood supply to the muscle – Increase mitochondria and store more oxygen – Improve digestion – Enhance neuromuscular coordination • Resistance exercise: – Increase muscle size

58 Regeneration of muscle tissue is

• Hypertrophy – enlargement of existing cells • Hyperplasia: – increase in the number of fibers (uterus) • Fibrosis: – replacement of muscle fibers by fibrous scar tissue

Gliding

• Flat bone surfaces move back-and –forth and side-to-side • No significant alteration of the angle between the bones • Limited to range

59 Flexion

• Decreases the angle between articulating bones

Extension • Opposite of flexion • Increases the angle between articulating bones • Hyperextension: – extension greater than 180°

60 Lateral flexion

• Involves intervertebral joints

Extension of the shoulder

61 Hyperextension moves a joint beyond the usual extended angle

• Abduction: – Movement away from the midline • Adduction – Movement toward the midline • Circumduction: – The continuous sequence of flexion, abduction, extension, adduction. – Example moving the humerus in a circle at the shoulder joint

62 • Rotation: – The bone revolves around its longitudinal axis

Special movement

• Elevation: – upward movement of a part of the body • Depression: – downward movement of a part of the body • Protraction: – movement of a part of the body anteriorly in the transverse plane • Retraction: – movement of protracted part back to the anatomical position.

63 Special movements of the foot • Inversion: – movement of the soles medially at the intertarsal joints – the soles face each other • Eversion: – Movement of the soles laterally at the intertarsal joints – The soles away from each other • Dorsiflexion: – Bending the foot and ankle in the direction of the dorsum – stand on your heels • Plantar flexion: – Bending the foot and ankle and the direction of the planter surface – Stand on your toes

Special movements • Supination: – a movement of the forearm at the proximal and distal radioulnar joint – the palm is turned anteriorly or superiorly i.e. anatomical position • Pronation – movement of the forearm at the proximal and distal radioulnar joints – the distal end of the radius crosses over the distal end of the ulna – The palms turn posteriorly or inferiorly • Opposition: – The movement of the thumb of the carpometacarpal joint – The thumb moves across the palm to touch the tip of the fingers on the same hand i.e. the ability to grasp

64 Nervous System

Structural Classification • Central nervous system (CNS) – Occupies the dorsal body cavity; Brain and spinal cord • Peripheral nervous system (PNS) – Cranial nerve and its branches – Spinal nerves and its branches – Ganglia (cell bodies outside the central nervous system) – Sensory receptors

65 Functional Classification of Peripheral Nervous System (PNS) • Somatic nervous system – Sensory neurons carry information from somatic receptors to the central nervous system (CNS) – Motor neurons carry impulses from CNS to skeletal muscles • Autonomic nervous system – Sensory neurons carry information from receptors in the visceral organs to CNS – Motor neurons carry impulses from CNS to involuntary muscles and glands

Histology of Nervous System

Two cell types: 1. Supporting cell (Also called Neurogliae or glia; glue cells) – Support, nourish and protect neurons. – Do not generate or propagate action potential – Can Multiply and divide (most brain tumors are glioma) – Six types • 4 in the CNS: Astrocytes, oligodendrocytes, Microglia, epindymal cells • 2 in the PNS: Schwann cells , and Satellite cells 2. Neurons: – Transmit nerve impulses

66 Neurons (nerve cell)

• consist of : 1. cell body contains Nucleus, Cytoplasm, Organelles (except centrioles), Nissl bodies (prominent clusters of rough ER, Neurofibrils ( maintain cell shape) 2. dendrites contains Short, and highly branched. The receiving portion of a neuron 3. axon: long branch

Axons

– Only one axon per neuron – Transmit nerve impulses away from the cell body – Axon terminals are fine processes at the end of the axon and contain vesicles that store the neurotransmitters

67 • Myelin sheath: – Multilayer lipid and protein covers the axons – Electrically insulates axons which increase the speed of nerve impulse – node of ranvier

• Nuclei: cell bodies in the CNS • Ganglia: small collections of cell bodies found in PNS • Tracts: Bundle of nerve fibers running through CNS • Nerves: Bundle of nerve fibers in the PNS • White matter: aggregations of myelinated fibers (tracts) • Gray matter: mostly unmyelinated fibers and cell bodies

68 Characteristics of neurons • Long-lived – Generally last a life time • Amitotic – neurons do not divide • High metabolic rate – This means high oxygen demand and lots of mitochondria – Neurons require glucose.

• Reflexes are rapid, predictable, involuntarily responses to stimuli • Types – Autonomic reflexes: • Regulate smooth muscles, heart, glands • Example: pupillary reflex – Somatic reflexes • All reflexes that stimulate skeletal muscles • Reflex arc elements: – Sensory receptor ( reacts to stimuli), Sensory (afferent) neuron, CNS integration center, Motor (efferent) neuron, Effector organ

69 Chemical Synapse Transmits a signal as Follows:

• Nerve impulse reach the synaptic end bulb of presynaptic axon • The vesicles release neurotransmitter into the synaptic cleft • neurotransmitter attach to the receptors in the postsynaptic neurons which result in depolarization.

Central Nervous System (CNS)

• Brain components – Cerebral hemispheres – Diencephalons – Brain stem – cerebellum

70 Cerebral Hemispheres • Paired, most superior part of the brain • Encloses most of the brain stem • the elevated ridges of the surface called gyri separated by shallow grooves called sulci • Fissures: – deeper groove separate large regions of the brain – cerebral hemispheres separated by longitudinal fissure • Fissures and sulci divide the hemispheres into lobes • Left hemisphere controls right side of the body and right hemisphere controls the left side of the body

Lobes of the cerebral hemisphere

• Frontal – Motor control area – Intellectual area • Parietal – General sensation • Temporal – For hearing and smell • Occipital – Visual area • Insula – For taste

71 Somatic sensory area

• located in the parietal lobe • The left side receives impulses from the right side and vice versa

Primary Motor area

• Allow us consciously to move our skeletal muscles • Located in the frontal lobe • The left side receives impulses from the right side and vice versa

72 Broca’s area

• Specialized area involved in our ability to speak • Found at the base of precentral gyrus • Located in only one cerebral hemisphere (usually left) • Damage to this area causes inability to say words properly

Speech area

• Located at the junction of the temporal lobe and the parietal lobe, and occipital lobe • Allow us to sound words • Only in one hemisphere, usually the left

73 • Higher intellectual reasoning located in the anterior part of the frontal lobe • Language comprehension (word meaning) located in the frontal bone

Diencephalons

• Thalamus: • Hypothalamus • epithalamus

74 • Thalamus – Relay station for sensory impulses passing upward to the sensory cortex

Hypothalamus • Under the thalamus • Connect to pituitary gland • Center of many drives and emotions; thirst, appetite, sex, pain, pleasure (connected to the limbic system) • Plays a role in the regulation of body temperature, water

75 Epithalamus • Epithalamus components – Pineal body • Secret melatonin. – Choroids plexus: • Secret cerebrospinal fluid

Brain stem

• Consist of – Midbrain – Pons – Medulla oblongata

76 • Cerebral aqueduct midbrain travels through the midbrain connecting the third ventricle to the fourth ventricle • Contain Reflex centers, involved in vision and hearing

Pons

• round structure protrudes below the midbrain • Have nuclei involved in breathing

77 Medulla Oblongata

• Most inferior part of the brain stem • Contain centers that control heart rate, blood pressure, breathing, swallowing, vomiting…etc.

cerebellum

• Projects dorsally from under the occipital lobe • Has two hemispheres and convoluted surface • Controls our balance

78 Menings • Three connective tissue covering the brain, from superficial to deep: 1. Dura mater: Leathery, outer most layer covers the brain and continues with spinal dura mater 2. Arachnoid mater: Has extensions span the subarachnoid space and attach to pia mater

Menings 3. Pia mater: clings tightly to brain surface and spinal cord following every fold • Arachnoid villi: protrude through dura mater, absorb CSF • Subarachnoid space: between the arachnoid and pia mater filled with CSF

79 Brain Ventricles

• Lateral ventricles in the cerebral hemispheres • Third ventricle in the diencephalon • Cerebral canal in the midbrain • Fourth ventricle between the pons and cerebellum

Cerebrospinal Fluid • Coroid plexus secret CSF in the ventricles • From lateral ventricles  to third ventricle  cerebral aqueduct  fourth ventricle  central canal of spinal cord and subarachnoid space  arachnoid villi  blood • changing in color, appearance, or composition, indicates disease. • Obstruction of circulation causes hydrocephalus

80 Cranial Nerves

• 12 pairs serve the head and the neck • Only the vagus nerve extends to the thoracic and abdominal cavities • Most cranial nerves are mixed nerves except: – Olfactory (I), Optic (II), and vestibulocochlear (VIII) are sensory nerves

Spinal Cord

• Enclosed in the vertebral column • Continuation of the brain stem • Extend from the foramen magnum to the first or second lumbar vertebra • Covered by meninges that extend beyond the spinal cord

81 Gray matter of spinal cord and spinal root

• Gray mater butterfly shape, surrounds the central canal • Ventral horn contains somatic motor neurons cell bodies that sends their axons out to the ventral root of the cord • Dorsal horn receives sensory axons. The cell bodies of sensory neurons are found in the dorsal root ganglion

White matter of the spinal cord

• Composed of myelinated fiber tracts (made up of axons ) • Divided into three regions in each side – Posterior column: has ascending tracts ( sensory) – Lateral and anterior columns has both ascending and descending (motor) tracts

82 Peripheral nervous system

• outside the central nervous system • Consist of: – nerves – ganglia

Structure of a Nerve

• A nerve is a bundle of neuron fibers outside the CNS. • Mixed nerves carry both sensory and motor fibers

83 Spinal nerves and nerve plexuses

• Spinal nerves – 31 pairs – Named for the region of the cord from which they arise from (cervical, thoracic, lumbar, sacral) • plexuses: – four plexuses that innervate the limbs

Autonomic Nervous System

• Two divisions have opposite effect – Sympathetic – Parasympathetic • Most organs have both innervations

84 Parasympathetic Division • Also called rest and digest • Active when the body is at rest • Allows us to conserve energy • Located in brain nuclei of four cranial nerves (III, VII, XI, X) send out their axons in cranial nerves to serve the organ in the head and neck region, and abdomen • Located in the sacral region (S2 through S4) of the spinal cord. They leave the spinal cord to pelvic cavity

Sympathetic division

• Also called fight-or- flight • Located in the spinal cord between T1 through L2 • Increase heart rate, blood pressure, glucose level, dilate bronchioles in the lungs, dilate blood vessels in skeletal muscle, withdrawal of blood from digestive organs

85 Special Senses

Senses

• Special senses – Taste, Smell, Sight, Hearing and balance – Large, complex sensory organs ( eyes, ears)

86 • Eye ball External and – Sphere, enclosed and protected accessory structures by the bony orbit • Eyelids: – protect the eyes anteriorly – Meet at the corners of the eye to form medial and lateral canthus • Eyelashes: – projecting from the border of each eyelid • Meibomian glands: – modified sebaceous glands in the eyelid – Produce oily secretion that lubricates the eye

Extrinsic Eye Muscles • Six muscles attach to the outer surface of each eye • Produce gross eye movement

87 Lacrimal apparatus

• Lacrimal gland – located above the lateral end of each eye – Secret tears into the anterior surface of the eye • Lacrimal canals – located medially • Lacrimal sac • Nasal Lacrimal duct: – empties into the nasal cavity

Conjunctiva

• lines the eyelids and covers the outer surface of the eyeball • Ends at the edge of the cornea • Secretes mucus that lubricate and moisten the eyeball

88 Sclera • Outermost, thick, white fibrous connective tissue (white of the eye)

Cornea: • The anterior portion, transparent, allows light to enters the eye.

Choroid

• Middle, blood rich layer • Ciliary body (muscle) attaches the lens • Iris: color of the eye has a round opening called pupil which regulates the amount of light entering the eye

89 Retina

• inner most layer • Contains photoreceptors except in the optic disc (blind spot) where the optic nerve exits the eye • Rods: Allow us to see gray tones in dim light • Cons: for accurate, colored (green, blue, red) vision. Concentrated in fovea centralis of macula lutea

Lens

• Flexible biconvex structure • Held by the suspensory ligament attached to the ciliary body • Divide the eye cavity into anterior chamber that contain aqueous humor and posterior chambers contain vitreous humor

90 Light Refraction

• The lens focuses the light on the retina macula lutea • The lens refractive power changes to properly focus the light on the retina – More convex  more refraction – Flatter  less refraction

Visual fields and visual pathways to the brain

• Optic nerve • Optic chiasm: • Optic tract: • Optic radiation • Occipital lobe

91 Eye reflexes

• Photopupillary reflex: – the pupils constrict immediately when exposed to bright light – Prevent damaging the photoreceptors • Accommodation pupillary reflex: – when viewing close objects; provide acute vision

Anatomy of the Ear

• Three major ears: – External and middle ear involved in hearing only – internal ear involved in hearing and equilibrium

92 External ear

• Composed of Auricle and earlobe surrounding the external auditory opening • supported by cartilage except ear lobe. • External auditory canal is short, narrow ends at the ear drum which separates the outer from the middle ear • Ceruminous glands in the skin secrete cerumen

Middle Ear

• Small air-filled cavity within the temporal bone • Located between eardrum laterally and a bony wall medially • Contains Ossicles: three bones (hammer, incus, stapes) that transmit vibration from tympanic membrane to oval window • Auditory (Eustachian) tube links the middle ear cavity with the throat. It equalizes the pressure in the middle ear with the external ear

93 Inner Ear

• located within the temporal bone behind the eye socket • Three subdivisions: – Cochlea contains organ of Corti (hearing) – Vestibule and semicircular canal for balance

Mechanism of hearing

• Sound waves enter the external auditory canal to the eardrum to the ossicles to the inner ear to the receptor cells in the organ of corti • The impulse carried by the cochlear nerve to the auditory cortex in the temporal lobe

94 Chemoreceptor

• Two kinds – Olfaction ( smell): wider range – Taste : four types

Olfactory receptors & sense of smell

• Olfactory receptors: – Very sensitive; pick up small differences – located in the roof of each nasal cavity • Olfactory pathway – Chemicals dissolve in mucus and stimulate the receptors. Then olfactory nerve carry it to the olfactory cortex • Olfactory pathway tied to limbic system (emotions) • Anosmias: – Loss of smell sensation due to trauma, inflammation, allergy • Olfactory auras: – olfactory hallucinations

95 Olfactory epithelium & pathway

Taste Buds & Sense of Taste • Four basic taste sensations: – Sweet: respond to sugar, saccharine, amino acids – Sour: acid – Bitter: alkaloids – Salty: metal ions • Other flavors are combination of the four tastes • Affected by sense of smell

96 Taste Buds & Sense of Taste

• Taste Buds – Receptors of taste sensation Found mostly on the tongue. – few taste receptors found in the soft palate and inner surface of the cheeks.

Endocrine System

97 The endocrine system • The Organs of the endocrine system are small. They Coordinates and directs the activity of the cells • Hormones released into the blood and transported throughout the body

Mechanisms of Hormone Action • Hormones attach to specific receptors on/in the cell and alter the cellular activity • Regulates processes such as: – Reproduction – Growth and development – Mobilizing body defenses against stressors – Maintaining electrolyte, water and nutrient balance of the blood – Regulating cellular metabolism and energy balance – Maintaining body homeostasis.

98 Steroidal hormones • Lipid-soluble molecules • binds to a specific receptor and to a specific sites on the cell’s DNA activating certain genes which result in the synthesis of new proteins.

Nonsteroidal hormones, protein and peptide hormones • The hormones binds to receptors on the target cell’s plasma membrane

99 Control of Hormone Release

• The stimuli that activate the endocrine organs fall into three major categories 1. Hormonal 2. Humoral 3. Neural

Hormonal stimulus

• Hypothalamic hormones stimulate the anterior pituitary gland to secrete its hormones • Anterior pituitary hormones stimulate other endocrine organs to release their hormones into the blood • As the hormones produced by the final target glands increase in the blood, they inhibit the release of anterior pituitary hormones; negative feed back

100 Humoral Stimuli • Blood levels of certain ions and nutrients stimulate hormone release • Examples – Decreased blood calcium levels will increase parathyroid hormone (PTH) secretion by the parathyroid glands

Neural Stimuli

• Nerve fibers stimulate hormone release • Example – sympathetic nervous system stimulate the adrenal medulla to release norepinephrine and epinephrine

101 The Major Endocrine Organs 1. Pituitary 2. Thyroid 3. Parathyroid 4. Adrenal 5. Pineal 6. Thymus 7. Pancreas 8. Gonads

Pituitary Gland

• Hangs by a stalk from the inferior surface of the hypothalamus • Located in the sphenoid bone • Has two lobes 1. Anterior pituitary secret 6 hormones – Growth hormone and prolactin affect nonendocrine targets – Thyrotropic, adrenocorticotropic hormone, and the two gonadotropic hormones stimulate endocrine glands, to secrete their hormones 2. Posterior pituitary: – Secrets ADH and Oxytocin

102 Growth hormone (GH)

• Affect skeletal muscles and long bones • Plays a role in determining final body size • Imbalance – Hyposecretion during childhood result in dwarfism – Hypersecretion during childhood results in gigantism – Hypersecretion after long bone growth has ended result in acromegaly (enlargement of facial bones, feet and hands, and thickening of soft tissues) – Most cases of Hypersecretion result from tumor cells producing the hormones

Prolactin (PRL) Adrenocorticotropic • target the breast and hormone (ACTH) stimulates and • Regulates the cortex of the maintains milk adrenal gland. production by the mother’s breasts Thyroid-stimulating • Its function in males hormone (TSH) is not known • Influences the activity of the thyroid gland.

103 Gonadotropic Hormones • Follicle Stimulating Hormone (FSH) – In female, stimulates follicle development in the ovaries. • As the follicles mature, they produce estrogen – In male, stimulates sperm development by the testes • Luteinizing Hormone (LH) – In female: • triggers ovulation and causes the ruptured follicle to become a corpus luteum • stimulates the corpus luteum to produce progesterone and some estrogen – In male • stimulates testosterone production by the testes. • IMBALANCE – Hyposecretion of FSH or LH leads to sterility in males and females

104 Hormones of the Posterior Pituitary

• Made in the hypothalamus; stored and secreted from posterior pituitary gland • Oxytocin – Stimulates uterine contractions during labor – Causes milk letdown in a nursing woman • Antidiuretic hormone (ADH). – causes the kidneys to reabsorb water which decrease urine volume and increase blood volume – In large amounts causes vasoconstriction which increases blood pressure – Alcohol inhibits ADH secretion – Hyposecretion of ADH causes diabetes insipidus

• Located in the neck Thyroid inferior to adam’s apple • Produce two hormones Gland • Thyroid hormone – Controls metabolism – Every cell in the body is a target – Important for normal tissue growth and development, especially the nervous systems • Calcitonin – Decreases blood calcium levels

105 IMBALANCE

• Hypothyroidism in early childhood may cause cretinism which results in dwarfism • Hypothyroidism in adults results in myxedema: – mental sluggishness, puffiness of the face, fatigue, poor muscle tone, low body temperature, obesity, and dry skin • Hyperthyroidism results in – a high basal metabolic rate, intolerance of heat, rapid heartbeat, weight loss, nervous and agitated behavior and a general inability to relax.

Goiter

• enlargement of the thyroid gland due to iodine deficiency • TSH stimulate thyroxin secretion  thyroid makes only the peptide part of the molecule which is nonfunctional hormone  Thyroid fails to provide negative feedback to inhibit TSH release  goiter

106 Graves’ disease

• Form of hyperthyroidism • the thyroid gland enlarges and the eyes may bulge, or protrude anteriorly

Parathyroid Glands

• Four glands on the posterior surface of the thyroid gland • some may be in other regions of the neck. • secrete parathyroid hormone (PTH) • Decrease blood calcium levels will increase PTH which increase calcium level in the blood • PTH also stimulates the kidneys to absorb more calcium

107 Adrenal Glands

• Two glands over the kidneys • Secret Glucocorticoids : – Mineralocorticoids – Glucocorticoids – Sex hormones. – EP and NE

Mineralocorticoids

• Mainly aldosterone. • Regulates sodium and potassium ions concentrations • When aldosterone rises, the kidney reclaim more sodium ions and excrete potassium ions in urine. • Water follows sodium reabsorption; helps regulate body fluids • Hypoaldosteronisim – Sodium and water are lost from the body, which leads to problems with electrolyte and water balance. This in turn, causes the muscles to become weak, and shock is a possibility • Hyperaldosteronisim – More water and sodium are retained, leading to high blood pressure and edema – potassium loss may disrupt heart activity and nervous system

108 Glucocorticoids • include cortisone and cortisol • response to ACTH secreted from the pituitary gland • promote normal cell metabolism and help the body to resist long- term stressors – Increase glucocorticoids level, the fats and proteins are broken down and converted to glucose, which is released to the blood • control inflammation • Glucocorticoids deficiency can cause – Hypoglycemia – Less ability to cope with stress – suppression of the immune system and increase susceptibility to infection. – Complete lack of glucocorticoids is incompatible with life

Cushing’s syndrome

• Excessive output of glucocorticoids results in a moon face, buffalo hump of fat on the upper back, high blood pressure, hyperglycemia and possible diabetes. • Weakening of the bones as protein is withdrawn to be converted to glucose, and severe depression of the immune system.

109 buffalo hump

Sex hormones • Mainly androgens (male sex hormones), some estrogens (female sex hormones) are also formed • HRMONAL IMBALANCE – Hypersecretion of the sex hormones leads to mascuilinization regardless of sex – In adult males, the effect may be masked – In females, a beard develops, and a masculine pattern of body hair distribution occurs, among other things.

110 • epinephrine and norepinephrine – increase heart rate, blood pressure, blood glucose levels, dilate the small passageways of the lungs • IMBALANCE – Hypersecretion of catecholamines leads to symptoms typical of excessive sympathetic nervous system activity • rapidly beating heart, high blood pressure, a tendency to perspire, very irritable

• The pancreases located behind the Pancreatic stomach • Pancreatic islets scattered among Islets exocrine cells. The islets produce two hormones 1. Insulin • Decrease blood glucose level • Insulin increases cell’s ability to transport glucose across the cell membranes • Decrease blood glucose level, the insulin release decreases 2. Glucagon • Antagonist to insulin • Increase blood glucose level • stimulates glycogenolysis in the liver, and the release of glucose into the blood

111 Diabetes Mellitus • Insulin deficiency leads to increase blood levels of glucose • Glucose appears in urine because the kidney cannot reabsorb it fast enough • The three cardinal signs of diabetes mellitus are: – Polyuria: urination – Polydipsia: thirst resulting from water loss – Polyphagia: hunger due to inability to use sugars

Pineal Gland

• Found on the roof of the third ventricle • Secret melatonin – The levels of melatonin rise and fall during the day and night. – Peak levels occur at night and make us drowsy

112 Thymus • Located in the upper thorax, posterior to the sternum. • produces a hormone called thymosin • during childhood the thymus involved in the maturation of T lymphocytes

Gonads • Ovaries – paired, almond-sized located in the pelvic cavity – produce ova and estrogens and progesterone – The ovaries begin to function at puberty • Testes – Paired, suspended in the scrotum, outside the pelvic cavity – produce sperm and male sex hormones, or androgens

113 Hormones of the Ovaries

• Estrogens – Stimulate development of female secondary sex characteristics – Estrogens work with progesterone to prepare the uterus to receive a fertilized egg. This results in cyclic changes in the uterine lining, the menstrual cycle. – Estrogens help maintain pregnancy and prepare the breasts to produce milk (lactation) • Progesterone – quiets the uterus so the implanted embryo will not be aborted – prepare breast tissue for lactation • Hyposecretion of the ovarian hormones stop the ability of a woman to conceive

Hormones of the Testes

• Testosterone – promotes the growth and maturation of the reproductive system in males – causes development of the male’s secondary sex characteristics (beard, heavy bones and muscles, voice) – stimulating the male sex drive – In adulthood, testosterone is necessary for continuous production of sperm • Hyposecretion, the man becomes sterile. • The function of the testes begin at puberty under the influence of the anterior pituitary gonadotropic hormones – Testosterone production is specifically stimulated by LH

114 Placenta • Formed in the uterus of pregnant women. • Function: respiratory and nutrition-delivery systems for the fetus and produces hormones • human chronic gonadotropic (hCG) – in early pregnancy, stimulates the corpus luteum to continue producing estrogen and progesterone • In the third month, placenta assumes production of estrogen and progesterone, and the ovaries become inactive for the rest of the pregnancy • estrogen and progesterone maintain pregnancy and prepare the breasts for producing milk • Human placental lactogen (hPL) works with estrogen and progesterone in preparing the breasts for lactation. • Relaxin: relaxes the mother’s pelvic ligaments and the pubic symphysis, which eases birth passage

Aging, changes occur in both sexes • The efficiency of the endocrine system gradually declines in old age • growth hormone output declines; explains muscle atrophy in old age • Elderly persons are less able to resist stress and infection • adult-onset diabetes is most common in the elderly

115 Blood

Blood • Blood transports nutrients, wastes, body heat …etc. through blood vessels • Consist of blood cells (formed elements) suspended in fluid (plasma) • Hematocrit – In a centrifuged blood sample, the formed elements precipitate and the plasma rises to the top – RBCs account about 45% of the total blood volume – WBCs and platelets contribute less than 1% – The remaining 55% is plasma

116 Physical Characteristics and Volume

• sticky opaque fluid • metallic taste • The color of blood varies from bright red (oxygen-rich) to a dull red (oxygen-poor) • pH between 7.35 and 7.45 • Accounts for approximately 8% of body weight. • in healthy males is 5 to 6 liters

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