unit 3 anatomy - brain and cranial nerves

neural tube

a groove formed in the top layer of differentiated cells in the embryo that eventually becomes the brain and spinal cord

formed by the neuroectoderm

rostral neural tube

"toward the nose" - brain

caudal

"toward the tail" - spinal cord, lower

Purple part

the part where the purple and green meet is the foramen magnum

cerebrum

largest and most superior part of the brain, divided into two convoluted cerebral hemispheres separated by a deep longitudinal fissure

cerebellum

s a brain region that coordinates voluntary movements, maintains balance and posture, and fine-tunes motor commands to make movements smooth and precise.

diencephalon

Part of the brain between the midbrain and cerebral hemispheres; includes thalamus and hypothalamus that are important. BLUE part

important in sensory and motor pathways with the ANS

not a part of brain stem

brainstem

stalklike portion, medulla, pons, and midbrain

pia

very thin, delicate membrane that closely follows all the contours of the brain surface

arachnoid

transparent membrane over the brain surface

dura

dense fibrous connective tissue, includes the periosteal and meningeal layer.

function of the dura, pia, and arachnoid

protect the brain and provide structural framework for arteries, veins, and blood sinuses

subarachnoid space

contains CSF

subdural space

between dura mater and arachnoid mater

epidural space

space between the dura mater and the wall of the vertebral canal

choroid plexus

floor or wall of ventricles, spongy mass of blood capillaries

CSF

liquid that fills the ventricles of the brain, central canal of the spinal cord, and space between the CNS and dura mater. secreted into ventricles by the choroid plexus and general ependymal lining

lateral ventricle

interventricular foramen

connects lateral ventricles to third ventricle, pore

third ventricle

the ventricle located in the center of the diencephalon

cerebral aqueduct

connects the third and fourth ventricles

fourth ventricle

the ventricle located between the cerebellum and the dorsal pons, in the center of the metencephalon

arachnoid villi (granulations)

extensions of the arachnoid mater that protrude through the dura mater into the superior sagittal sinus of the brain. reduce pressure on the CNS by draining CSF from the subarachnoid space into the bloodstream

dural venous sinuses

spaces that collect blood that has circulated through the brain

fissures

deep groves in the brain

sulcus

groove in the surface of an organ

gyrus

wrinkle or fold in the cortex of the cerebrum or cerebellum

precentral gyrus

upper motor neurons, primary motor cortex, anterior to the central sulcus

postcentral gyrus

sensory homunculus, posterior to the central sulcus, forms border of parietal lobe

frontal lobe functions

abstract though, explicit memory, mood, motivation, foresight, planning, decision making, emotional control, social judgement, voluntary motor control, speech production

partial lobe functions

taste, somatic sensation, sensory integration, visual processing, spatial perception, language processing, numerical awareness

temporal lobe functions

hearing, smell, emotion, learning, language comprehension, memory consolidation, verbal memory, visual and auditory memory

occipital lobe functions

visual awareness and visual processing

primary motor cortex

initiates and plans voluntary movements

primary somatosensory cortex

receives and processes sensory information from the body ex. touch, temp, pain, texture

homunculus

map along the cerebral cortex where each part of the body is processed

primary visual cortex

brain receives, processes, and integrates visual informtion

primary auditory cortex

receives and processes auditory information

limbic system

composed of parts of the cerebrum and diencephalon. plays a central role in memory, reproduction, emotion, mood, and nutrition

cingulate gyrus

plays role in expressing emotions via gestures and resolves mental conflict

hippocampus

A neural center located in the limbic system that helps process explicit memories for storage.

amygdala

A limbic system structure involved in memory and emotion, particularly fear and aggression.

thalamus

largest part, located inferior to the corpus callosum and bulging into each lateral ventricle, point of synaptic relay of nearly all signals passing from lower levels of the CNS to the cerebrum. "gateway to the cerebral cortex". major role in motor control, memory and emotional functions of the limbic system

hypothalamus

inferior portion, forming the walls and floor of the 3rd ventricle and giving rise to the posterior pituitary gland, controls many fundamental physiological functions

brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions

midbrain

short segment of the brainstem, connects hindbrain and forebrain. vision, hearing, sleep, wakefulness, arousal, and temperature regulation

pons

forms a broad anterior bulge in the brainstem just rostral to the medulla. facial sensations and expressions, eye movements, chewing, secretion of saliva and tears

medulla

begins at the foramen magnum of the skill and extends from 3 cm rostrally, ending at a transverse groove. regulates breathing, heart rate, blood pressure, breathing rate, blood circulation, and reflexes

reticular formation

loosely organized web of gray matter that runs vertically through all the levels of the brainstem and has connections with many areas of the cerebrum. functions include: pain modulation, sleep, consciousness, habituation, somatic motor control, cardiovascular control

olfactory nerve, CNI

smell

optic nerve, CNII

sensory

oculomotor nerve, CNIII

eye movements, opening of eyelid, pupillary constriction, focusing

trochlear nerve, CNIV

eye movements

abducens nerve, CNVI

lateral eye movement

facial nerve, CNVII

sensory : taste motor : facial expression, secretion of tears, saliva, nasal and oral mucus

vestibulocochlear nerve, CNVIII

hearing, equilibrium

glossopharyngeal nerve, CNIX

sensory : taste, touch, pressure, pain, and temperature sensations from tongue and outer ear, regulation of blood pressure, respiration. motor : salivation, swallowing, gagging

trigeminal nerve, CNV

V1, ophthalmic - touch, temp, pain sensations from upper face

V2, maxillary - V1, lower face

V3, mandibular - sensory - V1, V2 lower face. motor - mastication

accessory nerve, CNXI

swallowing, head, neck, shoulder movements

hypoglossal nerve, CNXII

tongue movements of speech, food manipulation, and swallowing

vagus nerve, CNX

sensory : taste, sensations of hunger, fullness, gastrointestinal discomfort motor : swallowing, speech, deceleration of heart, broncho-constriction, gastro-intestinal secretion, motility

sensory nerves

CNI-II, carry signals only from outlying sense organs to the brain. begin in receptors located mainly in the head and neck and lead to the brainstem

motor nerves

CN III, IV, VI, XI, XII. carry signals from the brainstem to outlying muscles and glands. begin in the nucleus of the brainstem and lead to glands and muscles

mixed nerves

CN V, VII, VIII, IX, X. carry signals both ways

cranial nerves

12 pairs, arise from the base of the brain, exit the cranium through its foramina, and lead to muscles and sense organs located mainly in the head and neck, labeled CN I - C XII, starting with the most rostal pair