Neuroanatomy - NEUR 3400 Chapter 7

Central Nervous System (CNS)

brain and spinal cord - integrative function

Peripheral Nervous System (PNS)

cranial and spinal nerves - sensory and motor function

orientation in the CNS

Rostral/Caudal

Ventral/Dorsal

- Anterior/Posterior

- Superior/Inferior

Afferent/Efferent

- Afferent -> Incoming sensory information

- Efferent -> Outgoing motor information

Contralateral/Ipsilateral

- Contralateral -> opposite side

- Ipsilateral -> same side

spinal cord anatomy

bony structures = vertebral column = spinal cord

three layers of meninges :

a. dura mater outer

b. arachnoid middle - spiderlike elastic collagen

c. pia mater inner - lots of blood vesicles

denticulate ligament - extension of pia mater - tooth like

spaces :

a. epidural - outer

b. subdural - middle

c. subarachnoid - inner - CSF

3 protective structures of the spinal cord

1) Vertebral Column

2) Meninges

3) Cerebrospinal Fluid (CSF)

internal anatomy of the spinal cord

gray matter = cell bodies, dendrites, and parts of axons

white matter = axons myelinated

central canal = CSF

spinal cord ascending and descending tracts

- ascending tracts are sensory axons that carry impulses upwards toward the brain

- descending tracts contain motor axons that conduct impulses downward, away from brain

tracts are bundles of axons in CNS

gross anatomy of the spinal cord

About 18 inches (45 cm) long

1/2 inch (14 mm) wide

Ends between vertebrae L1 and L2

Bilateral symmetry

two enlargements = cervical and lumbar

What are the two enlargements of the spinal cord?

cervical and lumbar enlargements

major regions of the brain

cerebrum, diencephalon, brainstem, cerebellum

protective structures of the brain

cranium = bony skull

cranial meninges:

a. duramater

b. arachnoid mater

c. pia mater

blood brain barrier - made up of astrocytes

ventricles of the brain

canals in the brain that contain cerebrospinal fluid

lateral ventricles - cerebral hemispheres

third ventricle - diencephalon

cerebral aqueduct - midbraon

fourth ventricle - brain stem and cerebellum

lateral ventricles of brain

ventricles found in each cerebral hemisphere

third ventricle of brain

Most central brain ventricle, ventral to the lateral ventricle, with the mesencephalic duct found inside it

in the diencephalon

cerebral aqueduct

a narrow tube interconnecting the third and fourth ventricles of the brain, located in the center of the mesencephalon

midbrain!

fourth ventricle of brain

The choroid plexus is located within this brain ventricle, found regionally under the cerebellum

brain stem and cerebellum!

What cells product most CSF?

ependymal cells

Blood Brain Barrier (BBB)

physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS

brain stem

medulla oblongata

pons

midbrain

houses cranial nerves 3-12 (10 pairs)

midbran aquaduct

fourth ventricle

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

cardiovascular and respiratory centers

pons

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

midbrain

A small part of the brain above the pons that integrates sensory information and relays it upward.

dopamine

control of movement and motivation

substantial nigra

cerebellum

gray matter = cell bodies outside

white matter = tracts inside

functions = coordinate movements, balance, learning

fourth ventricle

diencephalon

thalamus

hypothalamus

epithalamus

third ventricle

Thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

autonomic function

epithalamus

Contains pineal body. Involved in olfactory senses and sleep/wake cycle

no BBB

Cerebrum

cerebral cortex

cerebral tract

gyri = ridges

sulci = shallow grooves

fissures = deep grooves, valleys

lateral ventricles

Cerebrum (four lobes)

frontal

parietal

temporal

occipital

frontal lobe

mainly for motor thinking

high cognition

frontal association area

motor cortex

brocas area

parietal lobe

speech

somatosensory association

somatosensory cortex

taste

reading

wernickes area!

temporal lobe

smell

hearing

auditory association area

hippocampus

memory

occipital lobe

visual association area

vision

basal nuclei (cluster of neurons in CNS)

control initiation or termination of movement and thought

limbic system

neural system located below the cerebral hemispheres; associated with emotions and drives

hypothamalus

amygydala

spinal cord has

a core of gray matter surrounded by white matter.

gray matter inside

white matter outside

brain has

gray matter outside

white matter inside

spinal nerves

31 pairs of nerves arising from the spinal cord

cervical

thoracic

lumbar

sacral

coccygeal

cervical nerves

C1-C8 8 pairs

thoracic nerves

T1-T12 12 pairs

lumbar nerves

L1-L5 5 pairs

sacral nerves

S1-S5 5 pairs

coccygeal nerves

1 pair (Co1)

ganglia

clusters of soma in PNS

dorsal

sensory

ventral

motor

plexuses

Formed from groups of nerves that join together to do a common function after they have left the spinal cord

Cervical Plexus (C1-C5)

supplies neck and phrenic nerve to the diaphragm

phrenic nerves C3-C5

innervate the diaphragm

Brachial Plexus (C5-T1)

supplies shoulders and upper limbs

5 nerves :

radial (C5-T1)

median (C5-T1)

ulnar (C8-T1)

axillary (C5-T1)

musculocuntaneous (C5-C6)

long thoracic nerve (C5-C7)

radial nerve

Nerve that runs along the thumb side of the arm and the back of the hand

median nerve

Sensory-motor nerve that is smaller than the ulnar and radial nerves and that, with its branches, supplies the arm and hand.

thumb side of hand

ulnar nerve

Sensory-motor nerve that, with its branches, affects the little-finger side of the arm and palm of the hand.

pinky side of hand

axillary nerve

deltoid and teres minor

shoulder

musculocutaneous nerve

anterior upper lateral forearm

long thoracic nerve

scapula

Lumbar Plexus (L1-L4)

Femoral nerve:

- motor to anterior muscles of thigh na dot pectineus, iliacus

- skin of anterior and medial thigh via anterior femoral cutaneous branch

- Skin of medial leg & foot, hip & knee joints via saphenous branch

Sacral Plexus (L4-S4)

L4-S4

supplies the buttocks, perineum, and lower limbs

longest nerve - sciatic nerve!

sciatic nerve

nerve extending from the base of the spine down the thigh, lower leg, and foot

largest and longest nerve

injuries to sciatic nerve

sciatica = pain from buttock down posterior and lateral of leg

injury = herniated disc, dislocated hip, arthritis

injuries to brachial plexus

* C5-C8, T1

-some say is the most common shoulder injury

ulnar nerve palsy

median and ulnar nerve palsy

radial nerve palsy

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

cranial nerves

12 pairs of nerves that carry messages to and from the brain

PNS!

reflex arc

the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between.

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

stretch reflex

muscle contraction in response to stretching within the muscle

monosynaptic

-single synapse between sensory neuron that received and motor neuron responds

-e.g. knee jerk

ipsilateral

on the same side of the body

Contralateral

on the opposite side of the body

reciprocal

contraction of one muscle and relaxation of its antagonists