Exam #3 Anatomy 337 UW Madison

Divisions of the Brain

telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon

Telencephalon

cerebrum

Diencephalon

everything "thalamus"; hypothalamus, thalamus, epithalamus

Mecencephalon

midbrain

Metencephalon

pons and cerebellum

Myelencephalon

medulla oblongata; connection between spinal cord and end of the brain

Grey Matter

cell bodies, dendrites, unmyelinated axons; most of it is superficial

cortex: covers the surface of the brain

forms discrete internal clusters called cerebral nuclei

white matter

myelinated axons

cerebral hemispheres

anatomically mirror images, but differ functionally

only connected by a few white matter pathways: corpus callosum , anterior and posterior commissure

median longitudinal fissure

separates cerebral hemispheres

corpus callosum

connection between the right and left hemispheres

Brodmann's areas

different areas of the brain are given numbers; these areas are based on the regional cytoarchetechtonics of the cerebral cortex

1-52; differ in each person

functional areas of cerebral cortex

*Cerebral cortex is where cognition occurs, process information to create a response

- Mental processes such as awareness, knowledge, memory, perception, problem solving, decision making, information processing, and thinking

Motor areas:

- Control voluntary motor functions

Sensory areas:

- Provide conscious awareness of sensation

Multimodal association areas:

- Receive and integrate input from multiple regions of the cerebral cortex

frontal lobe

anterior part of cerebral hemisphere, central sulcus posteriorly, lateral sulcus inferiorly

prefrontal cortex: anterior portion of the frontal cortex

corpus callosum and TBI

usually damaged in TBI

even in mild concussion, brain moves in the skull which puts a lot of tension on fiber, added rotation, most anterior and posterior parts affected

cytoarchitecture

The arrangement of neuronal cell bodies in various parts of the brain; 6 layers of cerebral cortex, changes based on function

dorsolateral prefrontal cortex

executive functions: organization, planning, managing behavior, high-level decision making, multitasking, working memory, , helps with switching tasks

orbitofrontal cortex

modulating emotions, inhibition, adaptive learning, rewards, and emotion, ties emotion towards reward based learning, understanding outcomes and errors

anterior cingulate cortex

Motivational behavior

Reward-based learning: error detection, outcome monitoring

Pain processing (can lesion in brain)

Phineas Gage

railroad worker who survived a severe brain injury to frontal cortex that dramatically changed his personality and behavior; case played a role in the development of the understanding of the localization of brain function

primary motor cortex

voluntary motor activity, in the pre central gyrus (BA 4)

homunculus- entire map of the body on primary motor cortex

lower extremity- more medial, deeper in brain, face is majority of lateral aspect

pre-central gyrus

BA 4, beginning of the corticospinal tract, innervation can be diagramed as motor homunculus on the pre central gyrus

premotor cortex and supplementary motor cortex:

process motor information, plans and coordinated learned, skills motor activities, planning area for type of movement

where does the left motor cortex innervate

the right hand

broca's area

controls muscle actions needed for speech, inferolateral portion of the frontal lobe in the hemisphere

motor planning for language (speech, writing, sign language), only in left hemisphere

Broca's aphasia

condition resulting from damage to Broca's area (TBI or stroke), patients can understand spoken language but has difficulty communicating verbally

very aware they have this disorder, patients may be able to sing

parietal lobe

superoposteriar part of each hemisphere, central sulcus anteriorly, lateral sulcus inferiorly, parieto-occipital sulcus posteriorly

involved with general sensory function: tactile sensation, proprioception, taste, language, spatial orientation, and directing attention

where are the somatosensory cortices

parietal lobe

primary somatosensory cortex

receives general somatic sensory information from touch, pressure, pain, and temperature receptors; located within the postcentral gyrus BA 3,2,1

sensory homunculus

somatosensory association cortex

integrates and interprets sensory information

temporal lobe

inferior to the lateral sulcus, superior, middle and inferior gyrus, involved in hearing and smell, medial temporal lobe structures are associated with the limbic system- memory, learning, aggression, and emotion

superior gyrus of temporal lobe

auditory association area

Wernicke's area

language comprehension, recognizing and comprehending written and spoken language, within left hemisphere, overlaps parietal and temporal lobes

Wernicke's aphasia

fluent speech, impaired repetition and comprehension, wordy but meaningless speech, not aware they have a problem

hippocampus

medial temporal lobe structure that is essential in learning, storing memories, and forming long-term memory

working memory

used for temporarily storing and manipulating information

short term memory

characterized by limited capacity and brief duration

long term memory

may exist for limitless periods of time

patient HM

A patient who, because of damage to medial temporal lobe structures, was unable to encode new declarative memories.

Had seizures

Could learn new tasks, motor memory through cerebellum but couldn't remember what he had done, couldn't get better

amygdala

just anterior to hippocampus, contexts with many sensory association areas

functions: role in establishing association between sensory input and emotions, helps sort and code memories based on how they are emotionally perceived

involved in several aspects of emotion especially fear

insula

deep to lateral sulcus

primary gustatory cortex: processes taste information

limbic system

structures of the limbic system form a rink around diencephalon, structures collectively process and experience emotions, affects memory formation through the integration of past memories of physical sensations with emotional stress

experience pain, memory with emotion, formation of memory, intellectual functioning, and consciousness

cerebral nuclei (basal ganglia)

Paired gray matter nuclei deep within the white matter

- Caudate nucleus

- Putamen

- Globus pallidus

Control of posture and voluntary motor movements

- Adjust motor commands (refinement)

smoothness, coordination, posture and muscle tone

diencephalon

thalamus (relay center many synapses), hypothalamus (autonomic/endocrine), epithalamus (pineal gland which secretes melatonin sleep wake cycle)

grey matter surrounded by the cerebral hemisphere

cerebeullum

master coordinator, compares what we are trying to do with what we are actually doing learning a motor task, unconscious

cerebellum functions

Coordinates voluntary motor activity

- Precision, timing, and error‐correction

Control of muscle tone and posture

Motor learning and classical conditioning

- Eye blink, visceromotor conditioning, vestibuloocular reflex

Coordinates higher cognitive functions

- Problem solving, abstraction, directed attention

Coordinates emotional processing

All functions are ipsilateral!!!

brainstem

contains paired right and left structures and many autonomic centers and reflex centers for survival

brainstem function

consciousness and awareness, autonomic behaviors needed for survival, auditory and visual references, motor and sensory innervation to head and neck via CNs, mix nuclei

midbrain

motor functions, reticular formation, red nucleus

visual reflexes: superior colliculi

auditory reflexes: inferior colliculi

cerebral peduncles

midbrain, primarily motor axons, white matter pathway in corticospinal tract

substania nigra

neurons secret dopamine, control voluntary movements through connection to basal ganglia, associated with parkinson's disease, in the midbrain

red nucleus

midbrain, involuntary motor control

pons

contains corticospinal tract fibers, involved in primitive functions

regulation of breathing: autonomic nuclei in the pontine respiratory center

hearing: superior olivary nuclei receive auditory input and help localize sound

balance: nuclei that relay information from the cerebellum

sleep regulation

somtosensation: medial lemniscus

medulla oblongata

motor information, pyramids: corticospinal tract, pyramid decussation

autonomic nuclei group to form: cardiovascular center, and medullary respiratory center

other nuclei involved in coughing, sneezing, salivation, swallowing, gagging, vomiting

motor control

How the central nervous system integrates internal and external sensory information with previous experiences to produce a motor response.

visceral sensory

in conjunction with visceral motor, monitors things

somatic sensory

more voluntary; sense of touch

special sensory

special sense: vision, smell, hearing, vestibulation

visceral motor

unconscious control (digestive, blood vessel innervation, gland secretion)

somatic motor

voluntary movement, develops differently and goes to different muscles

how many cranial nerves originate in the brainstem

10

what are the four cranial nerves associated with the parasympathetic division?

oculomotor, facial, glossopharyngeal, vagus

cilliary ganglion

oculomotor nerve: ciliary muscle and to the pupillary constrictor muscle of the iris

pterygopalatine ganglion

facial nerve, lacrimal glands and small glands of nasal cavity, oral cavity, palate

submandibular ganglion

facial nerve, submandibular and sublingual salivary glands

otic ganglion

glossopharyngeal nerve, parotid gland

which two primary routes does blood take to the brain?

vertebral arteries, internal carotid

vertebral branches off the subclavian and are more protected by bones

Circle of Willis (cerebral arterial circle)

-Vertebral Arteries

-Anterior/Posterior communicating

-Anterior/Posterior cerebral

-Middle cerebral

-Internal Carotid

Allows blood from internal carotid and vertebral arteries to supply smaller cerebral arteries.

posterior cerebral artery

supplies posterior region and inferior part of the temporal lobe

middle cerebral artery

supplies lateral aspect of the brain

anterior cerebral artery

supplies superior part and the medial aspect

blood-brain barrier

functions to protect the brain

capillary endothelial cells and astrocyte perivascular feet contribute to it

astrocytes form tight junctions; continuous capillaries tight junction in endothelial cells; highly regulated

what connective tissue layers surround the brain?

dura, pia, and arachnoid mater

functions of cranial meninges

cover and protect the brain

enclose and protect blood vessels

stabilize the brain

contain CSF

Where is CSF housed?

subarachnoid space

arachnoid trabeculae

web like threads extending from arachnoid to pia mater; open up the space

epidural hematoma

can occur with a skull fracture or other trauma that damages the meningeal artery, often fatal unless treated quick

arterial bleed, bleeding between dura and skull, fast bleed

subdural hematoma

rapid acceleration or deceleration of the head; tearing of a cerebral vein as it pierces the arachnoid mater to enter a dural sinus

some process more quickly, others slower (venous bleed)

falx cerebri

separates the two cerebral hemispheres

falx cerebelli

separates the two hemispheres of the cerebellum

tentorium cerebelli

separates cerebrum from cerebellum

`cerebrospinal fluid

colorless fluid that circulates in the ventricles and subarachnoid space

produced by choroid plexus-ependymal cells

functions of csf

buoyancy, protection, environmental stability, hormone transport

circulation of csf

Lateral ventricles - interventricular foramen - 3rd ventricle - cerebral aqueduct - 4th ventricle - central canal of spinal cord or lateral apertures or median apertures - subarachnoid spaces- arachnoid granulations-dural venous sinuses

dura mater

dural venous sinuses

superior sagital sinus

inferior sagital sinus

transverse sinus

straight sinus

confluence of sinuses

Route of Blood Draining the Head

1. Superior Sagittal Sinus or Inferior Sagittal to Straight Sinus

2. Confluence of Sinuses

3. Transverse Sinus

4. Sigmoid Sinus

5. Internal Jugular Vein (merges with subclavian vein to form)

6. Brachiocephalic Vein (right and left merge to form)

7. Superior Vena Cava

8. Heart

nuchal

back of neck

infraorbital

below the eye

buccal

cheek

root of the neck

where cervical viscera, major blood vessels, and nerves pass from the head to the thorax

boundaries:

anterior: manubrium of the sternum

lateral: first ribs

posterior: T1 vertebrae

hyoid

between the mandible and larynx, does not articulate with any other bone or cartilage, attachment site for tongue and muscles of larynx used in swallowing

Crainial bones

8 bones

paired: parietal, temporal

unpaired: ethmoid, frontal, occipital, sphenoid

facial bones

14 bones

unpaired: vomer, mandible

paired: maxillae, nasal, lacrimal, zygomatic, palatine, inferior nasal conche

fontanelles

flexible areas of dense regular ct that connect the bones of the infant skull, present until many months after birth

posterior fontanelles close first, anterior closes over the first couple of year

anterior cranial fossa

frontal lobes, olfactory bulb, olfactory tract

middle cranial fossa

temporal lobe, pituitary gland

posterior cranial fossa

cerebellum

functions of the bones of the cranium

enclose and protect the brain;

provide attachment sites for muscles of the head and the neck

functions of the bones of the face

1. form the framework of the face

2. form cavities for the sense organs of sign, taste, smell

3. provide openings for the passage of air and food

4. hold the teeth

5. anchor the muscles of the face

Sternocleidomastoid

origin: manubrium (sternum) and clavicle

insertion: mastoid process

action: bilateral: flexes neck

unilateral: lateral flexion, rotation of the head to the opposite side

innervation: cn IX