THE BIG BRAIN EBOOK
By The Visible Body Team & Professor Blythe Nilson
Located inside the skull, the brain is an organ of the central nervous system that receives sensory input and information to form perception and thought. It controls activities such as speech, movement, and maintaining homeostasis. Forebrain
REGIONS OF THE BRAIN
The brain can be split into three regions: forebrain, brainstem, and cerebellum.
Cerebellum Brainstem
2 | Brain Regions Basal Ganglia Cerebral Cortex Corpus Callosum FOREBRAIN
The forebrain is made up of the cerebrum (cerebral cortex and basal ganglia), corpus callosum, diencephalon, and the limbic system.
Diencephalon Limbic system
Brain Regions>Forebrain | 3 CEREBRUM OVERVIEW
The cerebrum is the largest part of the brain. It is responsible for higher intellectual functions and conscious thought. The cerebrum is made up of the cerebral cortex and the basal ganglia.
4 | Brain Regions> Forebrain> Cerebrum Neuron diagram
CEREBRAL CORTEX OVERVIEW
The cerebral cortex is the surface of the cerebrum. The cortex contains around 16 billion neurons (cells that relay sensory sulcus information and motor commands as electric signals throughout the body). In order for the cerebral cortex to fit inside the skull, the cerebral cortex has folds called gyri and grooves called sulci.
gyrus Brain Regions> Forebrain> Cerebrum> Cerebral Cortex | 5 CEREBRAL CORTEX HEMISPHERES
The cerebral cortex consists of a left and a right hemisphere. The left is typically responsible for language, calculation, comprehension, and writing. The right is generally responsible for creativity, visual, emotional, and artistic awareness. Each hemisphere controls the opposite side of the body.
Left hemisphere Right hemisphere
6 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex Frontal Lobe Parietal Lobe
LOBES OF THE CEREBRAL CORTEX
Each hemisphere has four lobes: frontal, parietal, temporal, and occipital lobe. Each lobe is responsible for different brain functions.
Temporal Lobe Occipital Lobe
Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes | 7 Prefrontal association area Supplementary motor area (SMA) FRONTAL LOBE Premotor cortex Prefrontal association area: Executive function (thought, cognition, planning, and personality)
Premotor cortex: Planning movement
Supplementary motor area: Planning limb and eye movement
Broca’s area: Speech production and Primary motor area language processing
Gustatory cortex: Receives and processes taste signals
Broca’s area Gustatory cortex Primary motor area: Voluntary movement control
8 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes Primary somatosensory cortex PARIETAL LOBE Secondary somatosensory cortex
Primary somatosensory cortex: Processes tactile information (for the opposite side of the body)
Secondary somatosensory cortex: Processes tactile information (including pain)
Somatosensory association area: Integrates sensory input (perceives temperature, pressure, size, texture, and relationships between touched objects) Somatosensory association area
Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes | 9 TEMPORAL LOBE Secondary auditory cortex Auditory association area Auditory association area: Interprets Wernicke’s area auditory information such as speech, music, or other sounds Primary auditory cortex Primary auditory cortex: Interprets pitch and rhythm of sounds
Wernicke’s area: Comprehension of written and spoken language
Primary olfactory cortex: Receives and processes olfaction signals
Secondary auditory cortex: Processes auditory information and plays a role in Primary olfactory cortex Visual association area speech perception Visual association area: Participates in 10 | Brain Regions> Forebrain> Cerebrum> Cerebral Cortex> Lobes object and pattern recognition OCCIPITAL LOBE Primary visual cortex Primary visual cortex: Receives and processes visual signals from the Secondary visual cortex opposite visual field via the thalamus
Secondary visual cortex: Interprets visual signals and contributes to visual mapping
Tertiary visual cortex: Participates in Tertiary object recognition and motion sensing visual cortex
Brain Regions>Forebrain>Cerebrum>Cerebral Cortex> Lobes | 11
BASAL GANGLIA
The basal ganglia contain nuclei inside the cerebrum that influence body movement and muscle tone.
12 | Brain Regions> Forebrain> Cerebrum> Basal Ganglia CORPUS CALLOSUM
The corpus callosum is a c-shaped structure that straddles the midline of the brain. This connects the two hemispheres to allow communication between them.
Brain Regions> Forebrain> Corpus Callosum | 13 DIENCEPHALON OVERVIEW
The diencephalon is a region of the brain that consists of the hypothalamus, thalamus and epithalamus (main structure is the pineal gland).
Thalamus Epithalamus Hypothalamus
14 | Brain Regions> Forebrain> Diencephalon HYPOTHALAMUS
The hypothalamus regulates autonomic nervous functions, emotions, behavior, food consumption, circadian rhythms, and body temperature. It also produces hormones that influence the pituitary gland and regulate endocrine functions. At the base of the hypothalamus, the optic chiasm is the crossing point of the optic nerves.
Brain Regions> Forebrain> Diencephalon> Hypothalamus | 15 THALAMUS
The thalamus plays a role in learning and memory. It consists of several nuclei that pass sensory information to different regions of the cerebral cortex. The thalamus also determines what sensory information is important enough to send to the cerebral cortex to allow for conscious awareness of the sensory input.
16 | Brain Regions> Forebrain> Diencephalon> Thalamus PITUITARY
Hormones secreted by the hypothalamus activate hormone secretion by the pituitary gland. These hormones drive endocrine functions (like sexual development and promotion of bone and muscle growth) by targeting glands and tissues.
Brain Regions> Forebrain> Diencephalon> Pituitary | 17
Cingulate gyrus LIMBIC SYSTEM
The limbic system is located on the inner border of the cerebrum, above the diencephalon, forming a pair of rings between the two cerebral hemispheres. It manages a range of emotions and contributes to the processing of smell memory.
Amygdala = memory and emotion
Hippocampus = long term memory
Septal nucleus Mammillary body = smell memory Hippocampus Septal nucleus = feeling of pleasure
Amygdala Mammillary body Cingulate gyrus = expressing emotions through gestures
18 | Brain Regions> Forebrain> Limbic System Midbrain BRAINSTEM Pons The brainstem (consisting of the midbrain, pons, and medulla oblongata) connects the brain to the spinal cord. Medulla oblongata The brainstem controls the involuntary functions of the respiratory, digestive, and circulatory systems, while also contributing to hearing, balance, and gustation.
Brain Regions> Brainstem | 19 MIDBRAIN
The midbrain contains nuclei, called colliculi, which control visual and auditory reflexes. It also contains nuclei for the oculomotor (CN03) and trochlear (CN04) nerves. Both help control eye movement.
20 | Brain Regions> Brain Stem> Midbrain PONS
The pons connects the brain to the brain stem through tracts of white fibers that carry signals between them. It houses pontine nuclei, which affect breathing rhythms.
Brain Regions> Brain Stem> Pons | 21 MEDULLA OBLONGATA
The medulla oblongata controls involuntary functions of the respiratory, digestive, and circulatory system and contributes to hearing, balance, and taste. The medulla plays a role in homeostatis, acting as the autonomic reflex center for heart contraction, vasomotor control, respiratory rate and depth, as well as other reflexes such as swallowing, coughing, vomiting, and sneezing.
22 | Brain Regions> Brain Stem> Medulla Oblongata
CEREBELLUM
The cerebellum is mostly considered to be a motor structure. Even though motor commands do not directly come from the cerebellum, it modifies the commands to make the movements more accurate. This is why cerebellar damage leads to impairment in motor control. Other functions of the cerebellum include: maintaining balance and posture, coordination of voluntary movements, and motor learning, as well as some cognitive functions related to word association and puzzle solving.
Brain Regions> Cerebellum | 23 Central nervous system
PARTS OF THE NERVOUS SYSTEM
Peripheral nervous The brain is connected with the rest of system the body via the nervous system. The nervous system is responsible for the correlation and integration of various bodily processes, producing reactions and adjustments based on the current environment. The nervous system can be split into two different regions: the central nervous system (CNS) and the peripheral nervous system (PNS).
24 | Nervous System> Overview CENTRAL NERVOUS Brain SYSTEM
The central nervous system (CNS) consists of the brain and the spinal cord. The average length of a male spinal cord is 45 cm and for females, it is around 43 Spinal cord cm. The spinal cord carries incoming and outgoing messages between the brain and the rest of the body.
Nervous System> Central Nervous System | 25 PERIPHERAL NERVOUS SYSTEM
The peripheral nervous system (PNS) consists of all the nerves and ganglia outside of the central nervous system connecting it to all the regions of the body. The PNS can be split into two different divisions: the somatic nervous system (SNS) and the autonomic nervous system (ANS).
The somatic nervous system - controls all voluntary movement plus somatic reflexes
The autonomic nervous system - regulates involuntary movement such as heartbeat and smooth muscle contraction.
26 | Nervous System> Peripheral Nervous System CRANIAL NERVES
The cranial nerves are a group of 12 paired nerves in the peripheral nervous system that connect the muscles and organs of the head and some organs CN04 CN01 CN03 outside the head directly to the brain. CN02 CN01: olfactory = smell
CN02: optic = sight CN08 CN03: oculomotor = eye and pupil CN06 movement
CN04: trochlear = eye movement
CN06: abducens = eye movement
CN08: vestibulocochlear = hearing, balance Nervous System> PNS> Cranial Nerves | 27 CRANIAL NERVES, CONT’D. CN05 CN05: trigeminal = face sensation
CN07: facial = face movement, salivation
CN09: glossopharyngeal = taste, CN07 swallowing
CN10: vagus = heart rate, digestion
CN12 CN11: accessory = head movement CN09 CN12: hypoglossal = tongue movement CN11
CN10
28 | Nervous System> PNS> Cranial Nerves Circle of Willis
BLOOD SUPPLY TO THE BRAIN
The arteries deliver oxygenated blood from the heart to all the regions of the body. The left and right internal carotid and vertebral arteries supply the brain. The blood is distributed throughout the brain via the numerous branches of the Internal carotid circle of Willis.
Vertebral arteries
Blood in the Brain> Arteries | 29 Venous sinus Superficial cerebral veins
BLOOD SUPPLY TO THE BRAIN
Veins return deoxygenated blood to the heart. The largest vein in the brain is the venous sinus, located between the two hemispheres of the brain. It receives blood from the left and right superficial cerebral veins of the cerebrum. The blood is then drained via the left and right internal jugular veins Jugular veins
30 | Blood in the Brain> Veins PROTECTING THE BRAIN
The brain and the spinal cord are vital to the human body, so it is no surprise the body protects these structures at all costs.
The meninges is a set of protective connective tissue structures that surround the spinal cord and brain. The meninges consist of three layers, dura mater is the outermost layer; directly underneath the dura is the arachnoid mater; the pia mater is the innermost layer.
Protecting the Brain> Meninges | 31 Falx cerebri
PROTECTING THE BRAIN, CONT’D.
Within the brain there are double layers of dura mater, called cranial dural septa, that separate and support the brain. Two of these, the falx cerebri and the tentorium cerebelli, are highlighted in the picture.
Tentorium cerebelli
32 | Protecting the Brain> Meninges> Cranial Dural Septa PROTECTING THE BRAIN, CONT’D.
Inside the brain, there are networked ventricles that produce cerebrospinal fluid. This fluid moves between the ventricles transporting nutrients and wastes. It also provides structural support to the brain and protects against trauma.
Protecting the Brain> Ventricles | 33 BRAIN PATHOLOGY: PARKINSON’S
Parkinson’s disease is a neurodegenerative disorder that causes a progressive loss of fine motor movements. It is marked by decreased levels of dopamine in the brain. The resulting decrease in dopamine sent to the basal ganglia can lead to difficulties initiating movements. This can lead to tremors, impaired balance, and muscle stiffness. The disorder can also affect bladder function, speech, mood, or higher cognitive function.
34 | Brain Pathologies> Parkinson’s BRAIN PATHOLOGY: ALS
Amyotrophic lateral sclerosis (ALS) is a progressive disease that kills neurons of the motor cortex and peripheral motor nerves, inhibiting normal muscle control. Without signals from healthy motor neurons, normal muscle function ceases, causing spasm, weakness, and muscle death. This commonly leads to impaired movement and speech, trouble swallowing, and eventually respiratory failure.
Brain Pathologies> ALS | 35 BRAIN PATHOLOGY: EPILEPSY
Epilepsy is a neurological disorder characterized by recurrent seizures, which result from disruptions to the brain’s normal electrical activity. Different forms of epilepsy produce different types of seizures. The most common forms of stroke and hypertension can cause temporal lobe epilepsy producing focal aware seizures with altered hearing, sight, and speech, or focal impaired seizures with impaired consciousness and repetitive movements.
36 | Brain Pathologies> Epilepsy Healthy brain
BRAIN PATHOLOGY: ALZHEIMER’S
Alzheimer’s disease (AD) is the most common form of dementia among older Alzheimer’s disease people. Dementia is a brain disorder that seriously affects a person’s ability to carry out daily activities. AD begins slowly. It first involves the parts of the brain that control thought, memory, and language. Over time, symptoms get worse. People may not recognize family members or have trouble speaking, reading, or writing. Eventually, they need total care. Brain Pathologies> Alzheimer’s | 37 A universe of anatomical and physiological visuals and reference texts at your fingertips! www.visiblebody.com
View a 3D Tour of all the images featured in this eBook!
If you have a mobile version of Human Anatomy Atlas 2021.1 or later: 1. Click here to view the tour.
If you have a web version of Atlas: 1. Copy this link: https://apps.visiblebody.com/share/?p=vbhaa&t=4_31295_637546963103600120_507498 2. Use the share link button in the app. 3. Paste the link to view the tour.