Subdivisions of the Brain

what are the 6 subdivisions of the brain

1. cerebrum

2. diencephalon

3. cerebellum

4. midbrain

5. pons

6. medulla oblongata (medulla)

the brainstem consists of what (3)

1. midbrain

2. pons

3. medulla oblongata

functions of brainstem (2)

1. relay center for sensory input and memory output

2. responsible for many basic reflex actions

function of cerebellum

higher motor and sensory function

structures in the medulla (3)

1. pyramids

2. ANS centers

3. inferior part of 4th ventricle

what are the pyramids (in medulla)

bilateral ridges on anterior side of medulla that are composed of motor axons

most motor axons ______ in the pyramids in medulla

decussate

what does decussate mean

cross over

what does most motor axons decussating mean

generally, the left side of the brain controls movements of right side muscles and vice versa

what are the autonomic centers in the medulla (3)

1. cardiac center

2. vasomotor center

3. respiratory center

function of 4th ventricle

produce and distribute CSF

what is the pons mostly consisted of

chiefly composed of groups of axons (nerve fiber tracts)

what structures are located in the pons (2)

1. pontine respiratory center

2. superior part of 4th ventricle

function of cardiac center (in medulla)

regulates heart rate and strength of contraction (bp)

function of vasomotor center

constricts and dilates arterioles (constriction increases bp while dilation decreases bp)

function of respiratory center

regulates breathing rate (works w/ pontine respiratory center)

function of pontine respiratory center

helps control rate and depth of breathing

what structures are contained in the midbrain (3)

1. tectal plate

2. cerebral peduncles

3. cerebral aqueduct

where is the tectal plate

located on the posterior side of midbrain

the tectal plate is divided into (2)

1. superior colliculi

2. inferior colliculi

what is located in the superior colliculi

visual reflex centers

what is located in the inferior colliculi

auditory reflex centers

what are cerebral peduncles

groups of axons (nerve fiber tracts) on anterior side of midbrain

function of cerebral peduncles

conduct nerve impulses between the cerebrum and brainstem

function of cerebral aqueduct

connects the 4th ventricle to 3rd ventricle

what are the cerebellar peduncles (3)

1. superior cerebellar peduncles

2. middle cerebellar peduncles

3. inferior cerebellar peduncles

function of superior cerebellar peduncles

connects medulla to cerebellum

function of middle cerebellar peduncles

connects pons to cerebellum

function of inferior cerebellar peduncles

connects midbrain to cerebellum

functions of cerebellum (3)

1. coordinates and fine tunes skeletal muscle movements

2. maintains b balance and posture in response to info from proprioceptors

3. assists w/ regulation of behavioral expression, some cognitive skills, and language retrieval

what is ataxia

uncoordinated, jerky movements

how does alcohol and drugs affect cerebellar function

1. ataxia

2. disturbance of gait (walking pattern)

3. loss of balance and posture

4. inability to detect proprioceptive info

layers of cranial meninges (deep→superficial)

1. pia mater

2. subarachnoid space

3. arachnoid mater

4. dura mater

what layers make up the dura mater (deep→superficial)

1. inner meningeal layer

2. dural venous

3. outer periosteal layer

what are dural venous sinuses

large veins that drain blood from brain

functions of cerebrospinal fluid (2)

1. provides buoyancy for brain and spinal chord

2. maintains CNS chemical environment

T/F: CSF is produced continuously

True

what structure creates CSF

choroid plexus

where are the choroid plexus located

ventricles in the brain

choroid plexus = _______ + _________

1. blood capillaries

2. ependymal cells

ventricular system

1. left and right lateral ventricles

2. interventicular foramen

3. 3rd ventricle

4. cerebral aqueducts

5. 4th ventricle

CSF circulation process

1. CSF produced by choroid plexus in ventricles

2. CSF flows from lateral ventricle→interventricular foramen→3rd ventricle→cerebral aqueduct→4th ventricle→subarachnoid space

3. CSF removed via arachnoid vili in subarachnoid space

what are arachnoid villi

extension of arachnoid mater that project into dural venous sinuses

the diencephalon is composed of what (4)

1. epithalamus

2. thalamus

3. hypothalamus

4. 3rd ventricle

the walls and roof formed by the thalamus, hypothalamus, and epithalamus composes what?

3rd ventricle

what structure is located in the epithalamus

pineal gland

function of pineal gland

produces melatonin

function of melatonin

regulates circadian rhythm (24hr body clock)

what controls the epithalamus

hypothalamus

what is the thalamus

two oval masses of gray matter, covered in white matter

function of thalamus (2)

1. relay point and processing center for all sensory impulses (except olfaction) running to cerebrum

2. sensory info filter

functions of hypothalamus (7)

1. ANS control center

2. endocrine control center

3. body temperature regulation

4. water and electrolyte balance

5. regulation of hunger/food intake

6. regulation of sleep-wake cycles

7. control of emotional behavior

function of hypothalamus: ANS control center

1. control of involuntary of body

2. in charge of ANS centers in brainstem

function of hypothalamus: endocrine system

secretes hormones into bloodstream

the hypothalamus produces two hormones that are secreted by what

posterior pituitary

what 2 hormones does the hypothalamus produce that are secreted by posterior pituitary

1. oxytocin

2. antidiuretic

function of oxytocin

reproductive system→ bonding and lactation

function of antidiuretic hormone (ADH)

tells kidney to concentrate water when dehydrated

function of hypothalamus: body temperature regulation

senses temp of blood in vessels traveling through hypothalamus (temp to high = body releasing excess heat)

function of hypothalamus: water and electrolyte balance

examines blood in blood vessels for water/electrolyte balance

what is an electrolyte

ions and molecules that can carry an electric current

function of hypothalamus: regulation of hunger/food intake (hunger center, satiety center, and feeding center)

examines blood glucose levels

function of hypothalamus: regulation of sleep-wake (circadian) cycles

1. exposure to light→hypothalamus raises body temp and tells pineal gland to reduce melatonin secretion

2. exposure to dark: hypothalamus lowers body temp and tells pineal glad to increase melatonin secretion

function of hypothalamus: control of emotional behavior

express emotional feelings as physical changes (ex: blushing)

function of cerebrum

concerned with higher brain functions

what is in the gray matter (cerebral cortex)

where cell bodies are located

what is in the inner white matter (cerebral cortex)

axons (most but not all myelinated)

in general, each hemisphere controls the _______ side of the body

opposite

structures of cerebrum (4)

1. 2 cerebral hemispheres

2. longitudinal fissure

3. corpus callosum

4. cerebral cortex high convoluted

   1. gyrus

   2. sulcus

what is a gyrus (gyri)

raised/elevation of cortex

what is sulcus

depression or groove between gyri

what are the lobes of the brain (5)

1. frontal lobes

2. parietal lobes

3. temporal lobes

4. occipital lobes

5. insula

where does the frontal lobe end

ends at the central sulcus

what does the central sulcus do

separates frontal lobes from parietal lobes

what notable areas are located in the frontal lobe (2)

1. motor speech area

2. primary cortex

where is the motor speech area located

ONLY left frontal lobe

function of motor speech area

controls muscular movements needed for speech

what happens w/ damage to ONLY motor speech area

physically unable to produce speech but can still think about and interpret speech

location of primary motor cortex

precentral gyrus of both frontal lobes

function of primary motor cortex

controls voluntary skeletal muscle movement

the left primary motor cortex controls the _____-sided muscles and vice versa

right

location of parietal lobes

ends anteriorly at central sulcus and ends laterally at lateral sulcus

what is the lateral sulcus

groove that separates frontal and parietal lobes from temporal lobes

what notable areas are in the parietal lobe (2)

1. primary somatosensory cortex

2. wernicke area

location of primary somatosensory cortex

postcentral gyrus of both parietal lobes

function of primary somatosensory cortex

receives sensory input from skin, muscles, and joints

sensations from left side of body sent to the _____ cortex

right

location of wernicke area

overlaps areas in both parietal and temporal lobes

function of wernicke area (2)

1. helps us understand written/spoken language

2. helps us produce understandable speech

what happens if wernicke area is damaged

1. won’t be able to understand written/spoken language and/or not be able to produce understandable language

2. can physically speak but is gibberish

what notable area are located in the temporal lobe

1. primary auditory cortex

2. wernicke area

3. primary olfactory cortex

function of primary auditory cortex

receives and processes incoming sounds

function of primary olfactory cortex (2)

1. processes smell info

2. provides conscious awareness of smells

function of primary visual cortex

receives and processes incoming visual info

location of insula

deep to lateral sulcus

notable area involved in insula

1. involved w/ memory

2. primary gustatory cortex

function of primary gustatory cortex

involved in processing taste info