N2: Exterior Brain, Coverings & Blood Supply

location of the longitudinal sulcus

AKA the longitudinal fissure

• deep grove

• runs down the middle of the brain (front → back)

function of the longitudinal sulcus

• divides the brain into the R + L hemispheres

• allows each hemisphere to function somewhat independently

location of the right + left hemisphere

on either side of the longitudinal sulcus

function of the right hemisphere

controls the left side of the body

• creativity, music, emotion, spatial skills

function of the left hemisphere

controls the right side of the body

• language, math, reasoning

location of the brainstem

at the base of the brain

• connects the brain → spinal cord

function of the brainstem

it controls automatic body functions

• ex. breathing, swallowing, heartbeat, reflexes

location of the frontal lobe

the front part of the brain

• behind the forehead

function of the frontal lobe

• responsible for..

  • thinking

  • decision-making 

  • planning

  • movement

  • personality

• controls voluntary movement + emotional expression

location of the parietal lobe

located..

• behind the frontal lobe

• above the temporal lobe

function of the parietal lobe

processes..

• touch 

• temperature

• pain

• spatial awareness

→ generally helps you understand sensations + coordinate movements based on them

location of the occipital lobe

found at the back of the brain

function of the occipital lobe

responsible for vision + visual processing

• helps you recognize + interpret what you see (shapes, colours, motion) 

location of the temporal lobe

found on the side of the brain

• near your temples + ears

function of the temporal lobe

handles..

• hearing

• memory (long-term memory)

• language comprehension

location of gray matter

found..

• on the outer surface of the brain (cortex)

• in the nuclei of the brain 

what is gray matter made of

made mostly of neuron cell bodies

function of gray matter

help to process + interpret information

• responsible for thinking, memory, emotions + voluntary movements

what does gray matter of hemispheres form

they form...

• gyri + sulci

• large sulci = fissures

location of the cortex

the outer gray layer 

• covers both hemispheres of the brain 

function of the cortex

it handles conscious thought, sensation, movement + decision-making 

• “thinking-part” of the brain 

• controls everything you’re aware of doing 

what are deep gray matter

nuclei which are clusters of gray matter

• deep inside the brain

function of deep gray matter

they control automatic + movement-related functions 

location of white matter

found beneath the gray matter cortex

• throughout the brain

what is white matter made of

made up of myelinated axons

what are myelinated axons

long fibers of neurons

• covered in myelin (sheath) 

  • they speed up the transfer of information

function of white matter

myelinated axons = bundles that..

• connect (communicate) different areas of the brain 

  • either on the same or opposite sides

• form pathways that link the brain → spinal cord

location of the cerebrum

largest, topmost part of the brain

• divided into the R + L hemispheres

location of the cerebellum

at the back of the head

• under the cerebrum

• behind the brainstem 

function of the cerebellum

• controls balance, posture + coordination of movement

• fine-tunes signals from the cerebrum 

  • makes movement smooth + accurate 

parts of the brainstem

1. midbrain

2. pons

3. medulla (oblongata)

location of the midbrain

uppermost part of the brainstem

• just below the cerebrum 

function of the midbrain

• controls eye movement, pupil size

• controls reflexes to sound + light

→ helps coordinate visual + auditory responses

location of the pons

the middle part of the brainstem

• below midbrain

• above the medulla 

function of the pons

• acts as a bridge

  • which connects different parts of the brain

• helps to control breathing + facial movements 

• important for sleep + communication b/w the cerebellum + cerebrum 

location of the medulla (oblongata)

the lowest part of the brainstem

• directly connected to the spinal cord

function of the medulla (oblangata)

controls vital automatic functions

• ex. heart rate, blood pressure, breathing 

location of the lateral fissure

a deep groove on the side of the brain

function of the lateral fissure

• separates the frontal + parietal from the temporal lobe 

  • acts as a boundary line between the lobes

• helps identify the temporal lobe’s position 

location of the central sulcus

a deep groove

• running from the top → down 

• roughly in the middle 

function of the central sulcus

• separates the frontal lobe from the parietal lobe

  • divides the motor cortex (front) from the sensory cortex (back) 

• landmark between movement control areas from sensation areas

location of the pre-central gyrus

the ridge immediately in front of the centra sulcus

• in the frontal lobe

function of the pre-central gyrus

known as the primary motor cortex

• which controls voluntary muscle movement (ex. walking, writing, speaking) 

location of the post-central gyrus

the ridge immediately behind the central sulcus

• in the parietal lobe

function of the post-central gyrus

known as the primary somatosensory cortex

• which receives + interprets touch, temperature + pain

→ allows you to feel sensations + locate where they come from 

location of the pre-central sulcus

a small groove in front of the pre-central gyrus

• within the frontal lobe 

function of the pre-central sulcus

it separates the pre-central gyrus (motor area) from the premotor cortex

• which helps plan movements 

location of the post-central sulcus

a groove behind the post-central gyrus

• within the parietal lobe

function of the post-central sulcus

it separates the post-central gyrus (main sensory area) from the rest of the parietal lobe

• which processes spatial awareness + attention 

location of the superior frontal gyrus

runs along the top part of the front lobe

• above the middle frontal gyrus 

location of the middle frontal gyrus

lies between the superior / inferior frontal gyri

• in the frontal lobe 

location of the inferior frontal gyrus

found below the middle frontal gyrus

• in the lower part of the frontal lobe

• near the lateral fissure 

location of the superior temporal gyrus

the uppermost ridge of the temporal lobe

• just below the lateral fissure

location of the middle temporal gyrus

lies below the superior temporal gyrus

• above the inferior temporal gyrus

location of the inferior temporal gyrus

the lowest ridge of the temporal lobe

• near the bottom edge of the brain 

location of the superior parietal lobule

in the upper part of the parietal lobe

• behind the post-central gyrus 

location of the inferior parietal lobule

below the superior parietal lobule

• along the side of the parietal lobe 

what are primary cortex area

areas that receive/send the brain’s first signals for movement or sensation 

location of the primary motor cortex

on the pre-central gyrus

• in the frontal lobe

• in front of the central sulcus 

function of the primary motor cortex

controls voluntary muscle movements

• by sending commands from the brain → body 

• each side of the brain controls the opposite side 

location of the primary somatosensory cortex

on the post-central gyrus

• in the parietal lobe

• behind the central sulcus 

function of the primary somatosensory cortex

receives ““ sensations..

• touch

• temperature

• pressure

• pain 

→ allows you to feel + recognize sensations (like where something is touching you)

location of the primary auditory cortex

found on the superior temporal gyrus

• in the temporal lobe

• near the ears

function of the primary auditory cortex

processes sound information (pitch, rhythm, volume) 

→ essential for hearing + distinguishing different sounds

what are association areas

areas that interpret, connect + make sense of the signals received from the primary areas

location of the pre-motor area

• in the frontal lobe

• in front of the primary motor cortex

function of the pre-motor area

• plans + organizes movements 

  • BEFORE they happen

• coordinates movements that involve multiple muscles

• helps with learned movements (ex. typing, writing, playing an instrument) 

location of the pre-frontal cortex

the front-most part of the frontal lobe

• right behind the forehead

function of the pre-frontal cortex

handles thinking, decision-making, judgment, personality + emotion

• executive centre of the brain (helps you plan, focus + behave socially)

  • damage would cause poor judgment, impulsiveness or personality changes

location of the somatosensory association area

just behind the primary somatosensory cortex

• in the parietal lobe

function of the somatosensory association area

interprets + gives meaning to sensory information (like recognizing objects by touch without seeing them)

location of the common integrative area

in the parietal, temporal + occipital lobes

• where these regions meet (usually in the left hemisphere)

function of the common integrative area

combines information from different sensory areas (sight, sound, touch) 

• into a single understanding of what’s happening 

• helps you understand complex situations 

location of the vertebral arteries

travel up along the back of the neck

• through the foramina in the cervical vertebrae

• enters the skull through the foramen magnum 

function of the vertebral arteries

supplies blood to the posterior part of the brain

• includes the brainstem, cerebellum + occipital lobes

what is the basilar artery formed by

formed by the union of the 2 vertebral arteries

location of the basilar artery

runs along the front of the pons (2nd part of the brainstem) 

function of the basilar artery

• supplies the pons, cerebellum + midbrain 

• splits into the R + L posterior cerebral arteries

location of the internal carotid arteries

travels up the sides of the neck

• enters the skull though the carotid canals 

function of the internal carotid arteries

supplies the front part of the brain

• mainly the frontal, parietal + temporal lobes 

what is the circle of willis

it is a ring-like circle of arteries

location of the circle of willis

at the base of the brain

• around the pituitary gland 

function of the circle of willis

it acts as a backup system

• if 1 artery is blocked, blood can still reach other parts 

  • through alternate routes 

• provides redundancy 

  • protection from strokes (due to blockage in one area)

what is the circle of willis composed of

composed of 9 arteries in total.. 

1. internal carotid arteries (2)

2. anterior cerebral arteries (2)

3. anterior communicating artery (1)

4. posterior cerebral arteries (2) 

5. posterior communicating arteries (2)

location of the anterior cerebral artery (ACA)

extends forward + upward

• from the internal carotid artery

• runs along the midline between the hemispheres

function of the anterior cerebral artery (ACA)

supplies the medial (inner) surfaces of the frontal + parietal lobes

• medial surface, frontal pole

location of the middle cerebral artery (MCA)

extends laterally

• from the internal carotid artery

• into the lateral fissure 

function of the middle cerebral artery (MCA)

supplies the lateral parts of the frontal, parietal + temporal lobes 

• involved in face + arm movement, speech, hearing

• superolateral surface, temporal pole

location of the posterior cerebral artery (PCA)

branches off from the basilar artery 

• at the back of the circle of willis 

function of the posterior cerebral artery (PCA)

supplies the occipital lobe (vision) + inferior parts of the temporal lobes

• inferior surface, occipital pole

what is the midbrain supplied by

supplied by the posterior cerebral artery (PCA)

what is the pons supplied by

supplied by the basilar artery

what is the medulla supplied by

supplied by the vertebral arteries + its branches