Nervous System and Brain Pt. 2

bathes the external surface

what is CSF's function of the ventricles and canals?

40-70%

what percent of CSF is formed in the lateral ventricles?

up to 30%

what percent of CSF is formed in the 3rd and 4th ventricles?

100-160 mL

how much CSF is normally present at one time?

400-500 mL

how much CSF is produced in a day?

CO2; protein

CSF has more ____ and less ____ because the ependymal cells modify the filtrate from the blood plasma and capillaries of the brain

functions of CSF

bouyancy: allows brain to be its considerable size without being impaired by its weight. if it rested on the cranium the pressure would kill nervous tissue

protection: protects brain from striking the cranium when jolted. shaken child syndrome and concussions can still occur from severe jolting

chemical stability: flow of CSF rinses away wastes from the nervous tissue and regulates the environment.

lateral ventricle, interventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, foramen magendie, foramen luschka, subarachnoid space, and reabsorption in venous sinus

flow of CSF

hydrocephalus

abnormal accumulation of fluid (CSF) in the brain

increases intracranial pressure and size of ventricles over time

can cause variety of deficits

in babies: rapid increase in head size

surgical placement of shunt system to fix

10 sec

after how much time without blood flow to the brain would someone become unconscious

1-2 min

after how much time without blood flow to the brain would irreversible tissue damage occur?

4 min

after how much time without blood flow to the brain would death occur?

internal carotid artery

Supplies blood to the brain, eyes, eyelids, forehead, nose, and internal ear.

basilar artery

Serves the brain stem and the cerebellum as it travels upward

delivers to the pons

clot here is detrimental (sensory and motor info)

vertebral artery

delivers blood to the circle of willis

anterior cerebral artery

delivers blood to the medial part of the hemispheres

2

middle cerebral artery

delivers blood to the lateral part of hemispheres

70% of ischemic strokes occur because of a clot in this artery

posterior cerebral artery

supplies occipital lobe

if supply is cut off, vision problems occur

pyramids

crossing of motor fibers

carries motor signals to skeletal muscles

purple box

olives

prominent bulges lateral to each pyramid

has connections to the cerebellum

motor learning and coordination

light pink box

ascends upward

posteriorly, sensory info from the body of the medulla _____ to the thalamus

medulla

all nerve fibers connecting the brain to the spinal cord pass through where?

9, 10, 11, 12

what cranial nerves begin/end in the medulla?

cardiac, vasomotor, respiratory, and reflex

what are the 4 major centers of the medulla?

regulate HR

what does the cardiac center of the medulla do?

regulates if vessels are constricted/dilated

what does the vasomotor center of the medulla do?

regulates breathing

what does the respiratory center of the medulla do?

central pattern generators

neural pools that produce rhythmic signals to the muscles of breathing and swallowing

regulates vision/auditory reflex loops

what does the reflex center of the medulla do?

gracile nucleus

contains sensory info in the medulla

red box

fourth ventricle

brown box

cuneate nucleus

contains sensory info in the medulla

orange box

reticular formation

yellow box

reticular formation

loose network of nuclei extending throughout the midbrain, pons, and medulla (runs vertically)

contains cardiac, vasomotor, and respiratory centers

plays an important role in arousal

has connections with many areas of the cerebrum

more than 100 small neural networks within its distinct boundaries

medial lemniscus

The somatosensory pathway between the dorsal column nuclei and the ventral posterior nucleus of the thalamus.

green box

pons

A brain structure that relays information from the cerebellum to the rest of the brain

posteriorly

ascending sensory tracts through the pons pass where?

anteriorly

descending motor tracts pass through the pons where?

peduncles

what are the pathways in and out of the cerebellum?

5, 6, 7, 8

what cranial nerves are within the pons?

superior cerebellar peduncle

information highway

small oval near the fourth ventricle

middle cerebellar peduncle

large lateral dark spot

information highway

medial lemniscus

in the middle of the diagram the small rectangular shape

contains sensory information

corticobulbar and corticospinal tracts

motor information descending through pyramids

rounded bulbs located posteriorly

midbrain

connects hindbrain and forebrain

contains cerebral aqueduct

3 and 4

the midbrain contains the motor nuclei of 2 cranial nerves that control eye movements. which ones?

tectum

roof of the midbrain that is posterior to the cerebral aqueduct

contains the colliculi

superior colliculi

visual reflexes

light in one eye and both constrict

inferior colliculi

auditory reflexes

hearing something and turning to look

substantia nigra

An area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons

in Parkinson's disease this structure loses its dark color

cerebral peduncle

between the brainstem and cerebrum

blue star

functions of RF

somatic motor control

CV control

Pain modulation

Sleep and consciousness

Habituation

somatic motor control

RF adjusts muscle tension to maintain tone, balance, and posture during movement

CV control

cardiac and vasomotor centers of medulla oblongata

pain modulation

RF acts in the spinal cord to block the transmission of pain signals to the brain

nociception: pain sensation

sleep and consciousness

Reticular formation plays a central role in consciousness, alertness and sleep

Injury here can result in irreversible coma (no signals from RF to keep you awake)

Habituation

tendency of the brain to stop attending to constant, unchanging information

EX: feeling clothes on skin, sitting on a chair/couch

cerebellum

what is the largest part of the hindbrain?

vermis

what connects the R and L hemispheres of the cerebellum?

100 billion

the cerebellum contains more than half of all the brains neurons. about how many?

arbor vitae

white matter of the cerebellum

folia

folds of the cerebellum

gray matter contained here

four deep nuclei in each hemisphere

cerebellar functions

monitors muscle contractions and aids in motor coordination, evaluation of sensory input

timekeeping center

planning and scheduling tasks

evaluation of sensory input

- Comparing textures without looking at them

- Spatial perception and comprehension of different views of three-dimensional objects belonging to the same object.

timekeeping center

predicting movement of objects

helps predict how much the eyes must move in order to compensate for head movements and remain fixed on an object

planning and scheduling tasks

partly happens in the cerebellum and partly occurs in the frontal lobe

chiari malformation

part of cerbellum herniates down through foramen magnum

diencephalon

encloses the third ventricle

thalamus, hypothalamus, and epithalamus

thalamus

located in the middle of the brain

2 egg-shaped structures bilaterally

massa intermedia

the connection between the right and left thalamic nuclei

function of thalamus

sensory relay station

thalamus perception

bridge between sensory perception and cognition

sensing something and then coming to a conclusion about what it is

hypothalamus

nervous and endocrine tissue

functions:

HR and BP

body temp (shivering/sweating)

water and electrolyte balance

hunger and appetite (hormones)

activity of glands and tubes of digestive system (hormones)

sleep and wakefulness

regulates pituitary gland's regulation of growth, function of other glands, and reproductive function

pineal gland

regulates circadian rhythms

sleep-wake cycle

metabolic changes

cerebrum

largest part of the brain

many gyri and sulci (increase surface area)

precentral gyrus

primary motor cortex

postcentral gyrus

primary sensory cortex

lateral sulcus

separates the parietal and temporal lobes

parieto-occipital sulcus

separates parietal and occipital lobes