Anatomy Exam 2

CNS Structures

CNS Structures

brain and spinal cord

PNS structures

cranial nerves, spinal nerves, ganglia

sensory nervous system divisions

Motor nervous system divisions

neuron characteristics

• high metabolic rate, depend on glucose and oxygen

• extreme longevity

• can change but can’t divide

Unipolar neuron digram/parts and function

multipolar neuron diagram/parts

label parts of sc cross section

draw a basic spinal cord circuit

unipolar neuron sends info from skin to dorsal horn, multipolar interneuron relays signal w/in sc, multipolar neuron leaves ventral horn and leads to muscle

glial cells

nerve glue, assist neurons, protect, nourish, framework, ½ volume of nervous system, far outnumber neurons

afferent vs efferent

afferent = input

efferent = output

types of glial cells

CNS: astrocytes, ependymal cells, microglia, oligodendrocytes

PNS: schwann cells (neuromlemmocytes) and satellite cells

astrocytes

CNS, fill in space left behind when neurons die → framework, b/w neurons and capillaries of brain (form blood-brain-barrier)

Blood brain barrier

astrocytes: perivascular feet

capillary: tight junctions, continuous basement membrane

choroid plexus

capillaries + ependymal cells

ependymal cells

cns

bring fluid out of capillary and into cavity as CSF

microglia

cns

keeps cns clean of debris through phagocytic activity removing debris of dead neurons

oligodendrocytes

cns

attach to nearby axons and wrap cell membrane around them to form myelin

improve impulse speed

phospholipid bylayer

Neuron Depolarization & myelin

send impulse = depolarization = let Na+ in = make inside of neuron more positive (at rest charge outside is positive)

in myelinated neurons sodium only enters at nodes b/w myelin (faster!)

satellite cells

PNS

lines outside of unipolar neuron cell bodies

regulates delivery of nutrients and removal of waste products

neurolemmocytes (schwann cells)

myelenate peripheral neurons

nervous connective tissue

endoneurium: surrounds neurons

perineurium: surrounds fasicles

epineurium: surrounds nerves

Peripheral nerve damage/regrowth

neurolemmocytes form regeneration tube

neurolemmocytes release nerve growth factor

axon regrows 1-3 mm/day

parts of brainstem

Primary vessicles

secondary vessicles

what does the prosecephalon turn into?

→telencephalon→cerebrum

→diencephalon→thalamus, hypothalamus, epithalimus

what does the mesencephalon turn into?

→mesencephalon→midbrain

what does the rhombencephalon turn into?

→metencephalon→pons and cerebellum

→myelencephalon→medulla oblongata

directions when describing the brain

features of the cerebrum

wrinkles are gyri

grooves are sulci

deep grooves are fissures

white/grey matter of the brain, cerebral nuclei

pia mater

deepest: adheres to the surface of the brain

arachnoid mater

middle layer: has arachnoid trabeculae, stringlike projections attaching to pia mater

dura mater

outermost layer, periosteal dura is fused to the inside of the skull, while meningeal dura can peel away from periosteal layer to form structures (fural venous sinuses filled w/ blood)

label the missing parts (pink):

label the sinuses (and vein)

label the sinuses

label the ventricles/associated structures

label the ventricles/associated structures and explain the flow of CSF

flow of CSF starting point → sinus

name of the groove b/w left and right cerebral hemispheres

longitudinal fissure

Label the brain parts:

precentral gyrus

controls skeletal muscle on the opposite side of the body

postcentral gyrus

receives sensation from skin on the opposite side of the body

wernicke’s area

in parietal lobe, sensory speech: understand what someone is saying to you

primary visual cortex

at back of occipital lobe, receives info from eyes to allow sight, “projector screen”

primary auditory cortex

mid-superior temporal lobe: hearing

primary olfactory cortex

frontal superior temporal lobe: smell

broca’s area

in frontal lobe, motor speech: speak in a way that makes sense

what separates the frontal and parietal lobes?

central sulcus

what separates parietal and occipital lobes?

parieto-occipital sulcus

what separates frontal/parietal lobes from temporal lobe?

lateral fissure

insula: taste, awareness of self, perception of pain

left cerebral hemisphere functions

• right side motor control

• spoken and written language

• numerical and scientific skills

• reasoning

right cerebral hemisphere functions

• left side motor control

• musical/artistic awareness

• space and pattern perception

• insight

• imagination

• mental images

tracts

bundles of axons that connect different parts of the brain

association tracts

connect different parts of the same hemisphere

commissural tracts

connect one hemisphere to another (I.e. corpus callosum)

projection tracts

project from cerebral hemispheres down to brainstem and spinal cord

what structure is this?

thalamus

3 major parts of the diencephalon

thalamus

relays somatosensation (sensation we are aware of) to proper lobe of cerebral cortex

hypothalamus

• controls ANS

• controls endocrine system

• reg. body temp

• controls emotion

• thirst & hunger

• circadian rhythm

epithalamus

pineal gland secretes melatonin

parts of the brainstem

Midbrain features and functions

superior colliculi

track objects w/ eyes, predict trajectory

inferior colliculi

track objects based on the sounds they make

substantia nigra

cerebellum

• perform actions with great precision

• process cerebrum’s signals and smooth them out

• damage→ataxia (jerky movement)

pons

(middle of brainstem)

respiratory control

medulla oblongata

(bottom of brainstem) cardiac and respiratory control

Cranial nerve name mnemonic

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cranial nerve motor, sensory, or both mnemonic

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CN I

olfactory nerve

smell, receptors on roof of nasal cavity

CN I passage through skull

cribiform plate of ethmoid bone

CN II

optic nerve

vision, receptors in retina of eye (info projected to same and opposite side of the brain)

CN II pathway through skull

optic foramen

label the eye muscles

how to remember which cranial nerves control which eye muscles

how does the inferior oblique move the eye?

up and out

how does superior rectus move the eye?

up and in

how does the medial rectus move the eye?

inward

how does the inferior rectus move the eye?

down and in

how does the superior oblique move the eye?

down and out

how does the lateral rectus move the eye?

outward

how do cranial nerves III, IV, and VI reach the orbit?

superior orbital fissure

CN III

oculomotor nerve:

• superior rectus

• levator palpebrae superioris

• medial rectus

• inferior rectus

• inferior oblique

CN IV

trochlear nerve: superior oblique

CN VI

abducens nerve: lateral rectus

CN V-1

opthamalic branch of trigeminal nerve:

• forehead and nose skin sensation

• cornea sensation

CN v-1 skull pathway

superior orbital fissure

CN V-2

trigeminal - maxillary branch

• sensation of skin b/w inferior eyelid and mouth

• sensation from upper teeth

CN V-2 Pathway through skull

foramen rotundum

CN V-3

mandibular trigeminal

• skin around mandible sensation

• sensation from lower teeth

• general (touch) and special (taste) sensation from tongue

• somatic motor to muscles of mastication

  • only V-3 has motor!

CN V-3 pathway through skull

foramen ovale

label pathways and which trigeminal branches pass through them

label the salivary glands