lecture 13 4/12

Cervical enlargement

supplies nerves to the pectoral girdle and upper limbs

Enlargements

are expanded forms of the spinal cord

the lumbosacral enlargement

supplies nerves to the pelvis and lower limbs

conus medullaris

inferior to the lumbosacral enlargement, the spinal cord tapers (lowering thickness) to a conical tip called the conus medullaris

Cauda Equina

is a collection of lumbosacral and coccygeal spinal nerves located within the subarachnoid space inferior to the conus medullaris

where does the term cauda equina come from?

The term cauda equina comes from the term “Equus” meaning horse because it looks like a horses tail

posterior median sulcus

shallow indentation along posterior midline of spinal cord

anterior median fissure

deep indentation along anterior midline of spinal cord central c

central canal

is where cerebrospinal fluid runs through the spinal cord (to bathe cells in the spinal cord)

posterior dorsal gray horn

location of somatic and visceral sensory nuclei within all spinal cord segmentsateral

lateral Gray Horn

location in T1-L2 spinal cords segments only: location is visceral motor neurons of automatic nervous system (ANS)

anterior ventral gray horn

location of somatic motor neuron within all spinal cord segments

gray commissure

is the gray matter between left and right side of spinal cord, surrounding central canal

posterior dorsal white column

location of: fascicles gracilis, and fascicles cuneatus for “conscious” proprioception and fine touch, pressure and vibration

if you damage these you can loose sensation

anterior (ventral) white column has how many location?

3, anterior spinothalamic tract, anterior corticospinal tract, and medical pathway tracts. H & I; ventral corticospinal tract axon carry motor info for posture bilateral movements

the anterior spinothalamic tract

is a major pathway in the spinal cord that transmits sensations of crude touch and pressure to the brain, running alongside the spinothalamic tract.

anterior corticospinal tract

for conscious motor commands

medial pathway tract

reticulospinal, vestibulospinal, tectospinal- for subscoscious and reflexive motor control

Lateral white column how many locations?

4, anterior and posterior spinocerebellar tract, lateral spinothalamic tract, lateral coticospinal tract and rubrospinal tract

anterior and posterior spinocerebellar tract

unconscious propriception that relays sensory information from the lower body and limbs to the cerebellum for coordination of movement.

lateral spinothalamic tract

for pain and temperature sensation

lateral corticospinal tract

for conscious motor commands

rubrospinal tract

subconscious coordination of limb movements

dorsal root

contains the axons of somatic sensory neurons (axons leaving spinal cord)

dorsal root ganglion

contains the cell bodies of sensory neurons (psudounipolar) K&M

ventral root

contains the axons of motor neurons (axons entering spinal cord) (somatic and visceral) L &N motor spinal nerves

dorsal Ramus

axon that receive sensory innervation from, and transmits motor innervation to deep back muscles

ventral ramus

axons that receive sensory innervation from, and transmits motor innervation to anterior and lateral body wall and extremities

rami communicantes

found at T1-L2 spinal nerves only, contains sympathetic visceral motor fibers (axons)

Sympathetic chain

contains axons of sympathetic pre-ganglionic neurons

sympathetic chain ganglion

contains cell bodies of sympathetic postganglioic neuron ptm

motor pathways: how do we initiate movement?

lateral corticospinal pathway; control fine muscle movement, causes movement on other side of the body, descends lateral

how do we initiate movement?

1. neurons from cereal cortex decussate (cross over) in medulla

2. neuron travels through lateral corticospinal tract

3. neuron causes muscle movement via interneuron in ventral horn

4. if you want to move right, your left side of the brain will cause the movement

how do we sense touch and vibration?

dorsal column: sensing touch vibration, ascends ipsilateral thought the dorsal column white matter tract, lateral dorsal column, arms/hands, medical dorsal column ( legs/ feet)

how do we sense touch and vibration?

1. You sense touch from your left hand. Sensory information travels through dorsal root and ascends through lateral dorsal column.

2. sensory neuron communicated with neuron from medulla

3. neuron form medulla decussated and then communicated with neuron in the thalamus

4. neuron travels to cortex and you fell touch form the left hand in the right side of the brain

how do we sense pain and temperature?

spinothalamic pathway: senses pain and temperaturewh

how do we sense pain and temperature?

1. you sense from your left hand. the sensory neurons travels through the dorsal root and enter the dorsal horn.

2. the sensory neuron communicated with neuron in spinal cord and this neuron crosses over to the right side of the spinal cord

3. the neuron ascends contralateral through the spinothalamic tract and then communicated with neuron in the thalamus

4. thalamic neuron travel to the cortex and you feel pain from your left hand in the right side of the brain.

dura mater

forms the outermost covering of the spinal cord. the outer and inner surfaces are covered by epithelium/ This is part of the meninges

arachnoid mater

is the middle layer of the meninges and consists of simple squamous epithelium

pia mater

is the innermost layer of the meninges. formed by elastic and collagen fibers of the pica mater.

denticulate ligament

are lateral extensions of the spinal Pia mater that connect the pica mater and spinal arachnoid mater to the dura mater. stabilizes the spinal cord

filum terminale

is slender stand of fibrous tissue that extends from the inferior tip of the conus medullaris along the length of the vertebral canal as dar as the coccyx. also stabilization of spinal cord

subarachnoid space

inferior to this layer is a small space filled with cerebrospinal fluid (CSF)

arachnoid mater

is the middle meninges and consists of simple squamous epithelium

epidural space

is more superficial to the dura mater, but does not have direct contact with the dura. It contains areolar tissue, blood vessels, and adipose tissue.

what is the name of the posted tip of the spinal cord?

conus medullaris

name the meninges layering from innermost to outermost?

pia mater, archnoid, dura mater

what is the denticulate ligament?

prevents the spinal cord to move form side to side

What is the cauda equina?

thinning of the spinal cord.

which part of the brain if damaged would cause a more severe symptom and why? medulla oblongata or frontal lobe

Damage to the brainstem can cause more severe symptoms due to its role in regulating vital functions such as breathing and heart rate.

what is the function of the cerebellum

motor coordination

what part of the brain receives visual information

the occipital lobe, which processes visual data received from the eyes.

what part of the brain does the critical thinking occurs

prefrontal cortex

gustatory cortex

is responsible for processing taste information. neurons in this cortex receive tasting information.

what is the functional difference between the superior colliculi and the inferior colliculi?

the superior colliculi is the visual reflex center of the midbrain. The inferior colliculi is the auditory reflex center.

how is the information from he cerebellum and pons connected anatomically?

relays sensory information to cerebellum and thalamus

What chemical does the substance nigra release?

The subastnia nigra releases dopamine, which is essential for movement control.

what is the function of the pineal gland?

The pineal gland regulates sleep-wake cycles by producing melatonin, a hormone influenced by light exposure.

name the 4 parts of he dura mater

Falx cerebri, Tentorium cerebelli, falx cerebelli, diaphragma sellae

describe the anatomy of CTE/ Concussions

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease characterized by the accumulation of tau protein in the brain, resulting from repeated head injuries. Symptoms can include memory loss, impaired judgment, impulse control issues, and progressive dementia.

write out the pathway of CSF circulation

lateral ventricles> interventricular foramina> third ventricle> cerebral aqueduct> fourth ventricles> lateral and median aperture> subsarachnoid space

how does the pupil dilate?

contraction of the muscles of the iris will change the diameter of the pupil

where does the gritty eye deposits (eye booger) form?

lacrimal caruncle

which layer of the eye wall holds the lend in place?

the ciliary body

what happened to the side of the lens if you sent to see a nearby object?

ciliary muscles, suspensory ligaments relax, lens is rounded, focusing on near distant objects

how does a red eye occur?

layer of stratified squamous epithelium covering the inner surface of the eyelids and covering the outer surface of the eye, both are mucous membrane, infection of this causes red eye.

list the 9 steps of the visual pathway

1. rods and cones: conversion of visual signal to electrical impulse

2. rods and cones pass electrical impulses to bipolar cells layer

3. bipolar cells pass the signal to ganglion cell layer

4. axon and the ganglion cells join each other to become optic nerves

5. optic nerve crosses at optic chiasm

6. optic tract

7. lateral geniculate nucleus of thalamus

8. projection fibers (or superior colliculus or other parts of brain)

9. visual cortex of occipital lobes