Module 10 - Central and Somatic Nervous Systems

the spinal cord is located

in the vertebral canal of the vertebral column

beyond the bones themselves, the spine is protected by (3)

cerebrospinal fluid, meninges and vertebral ligaments

3 layers of connective tissue covering that extend around the spinal cord and brain?

meninges

true/false: spinal meninges are continuous with cranial meninges.

true

tough, dense, irregular connective tissue that extends to 2nd sacral vertebra (outermost later of meninges)

dura mater

arrangement of collagen and elastic fibers that resembles a spiders web (middle later of meninges)

arachnoid mater

transparent layer of collagen and elastic fivers containing numerous blood vessels that adheres to the surface of the spinal cord and brain (innermost meninges layer)

pia mater

space between the arachnoid and pia mater where cerebrospinal fluid circulates

subarachnoid space

refers to the nerves of the lumbar, sacral and coccugeal regions that do not exit the vertebral column where they exit the cord and instead go down since cord ends at 2nd lumbar vertebrae.

cauda equina

spinal cord enlargement that contains nerves that supply the upper limbs ?

cervical enlargement

spinal cord enlargement that contains nerves supplying the lower limbs ?

lumbar enlargment

anteriorly divides the spinal cord into left and right?

deep anterior median fissure

posteriorly divides the spinal cord into left and right?

shallow posterior median sulcus

small space in the centre of the spinal cord grey matter containing cerebrospinal fluid

central canal

the paths of communication between the spinal cord and specific regions of the body

spinal nerves

root containing sensory axons that conduct nerve impulses from sensory receptors in the skin, muscles and internal organs into the CNS.

posterior root

each posterior root contains a swelling containing the cell bodies of sensory neurons called

posterior root ganglion

root that contains axons of motor neurons that conduct nerve impulses from CNS to effectors.

anterior root

contain cell bodies and axons of interneurons and axons from incoming sensory neurons

posterior grey horns

contain cell bodies of somatic motor neurons that provide nerve impulses for contraction of skeletal muscles

anterior grey horns

contain cell bodies of autonomic motor neurons that regulate the activity of smooth muscle tissue, cardiac muscle and glands

lateral grey horns

present only in thoracic and upper lumbar segments of the spinal cord?

lateral grey horns

divided into anterior, lateral and posterior columns?

spinal cord white mater

axons that conduct nerve impulses towards the brain?

sensory tracts

axons that carry impulses down the spinal cord?

motor tracts

connect the CNS to sensory receptors, muscles and glands?

spinal nerves

\___ pairs cervical, \___ pairs thoracic, \___ pairs lumbar, \____ pairs sacral, \___ pairs coccygeal

8, 12, 5, 5, 1

first pair of cervical spinal nerves emerge?

above the atlas

other then the first pair, all other spinal nerves exit the spinal cord through?

intervertebral foramina

before exiting the intervertebral foramina, 2 parts come together to making them mixed nerves

anterior and posterior roots

connective tissue wrapping each individual axon?

endoneurium

groups of axons bundles together into fascicles are wrapped in?

perineurium

the superficial covering over an entire nerve?

epineurium

as the spinal nerve passes through the intervertebral foramen, the dura mater of the spinal meninges fuses with the ...

epineurium

many blood vessels are present in these neuriums to nourish the nerves.

epineurium and perineurium

areas where spinal nerves branch and join with axons of nerves forming networks that then reach the areas being served.

plexuses

4 major plexuses?

cervical, brachial, lumbar and sacral plexuses

nerve plexus that supplies the skin and muscles of the posterior head, neck , upper part of the shoulder and the diaphragm?

cervical plexus

stimulate the diaphragm to contract?

phrenic nerves

plexus that supplies the upper limbs and several neck and shoulder muscles?

brachial plexus

these nerves are part of what plexus?
musculocutaneous, axillary, median, radial and ulnar nerves

brachial plexus

plexus that supplies the abdominal wall, external genitals and part of the lower limbs?

lumbar plexus

ilioinguinal, femoral and obturator nerves arise in what plexus?

lumbar plexus

this plexus supplies the buttocks, perineum and lower limbs?

sacral plexus

gluteal, sciatic, pudendal nerves arise in the ?

sacral plexus

longest nerve in the body?

sciatic nerve

spinal nerves T2 to T11 that do not form plexuses and extend directly to the structures they supply

intercostal nerves

nerves that supply the muscles between ribs, abdominal muscles and skin of the chest and back?

intercostal nerves

a fast, involuntary sequence of actions in response to a particular stimulus.

reflex

2 type of reflexes?

inborn and learned

type of inborn reflex when you pull your hand off something hot?

withdrawal reflex

reflex where integration happens in the spinal cord grey matter?

spinal reflex

reflex where integration happens in the brain stem? (ex. tracking eye movements)

cranial reflex

the pathway followed by nerve impulses to produce a reflex?

reflex arc

knee jerk reflex is called the

patellar reflex

5 players involved in a patellar reflex from start to movement?

sensory receptor, sensory neuron, integrating center, motor neuron and effector

if the effector is skeletal muscles, the reflex is a?

somatic reflex

if the effector is smooth muscle, cardiac muscle or a gland, the reflex is a ?

autonomic reflex

swallowing, urinating and defecating all involve this type of reflex?

autonomic reflexes

4 main parts of the brain?

brain stem, cerebellum, cerebrum and diencephalon

is continuous with the spinal cord and consists of the: medulla oblongata, pons and midbrain?

brain stem

located above the brain stem and consisting mostly of the thalamus, hypothalamus and pineal gland.

diencephalon

the bulk of the brain, supported by the diencephalon and brain stem?

cerebrum

located posterior to the brain stem?

cerebellum

protects the brain from harmful substances and pathogens by preventing the passage of many substances from blood to brain (tightly sealed blood capillaries and astrocytes). The...

blood brain barrier

type of substance that can easily cross the blood brain barrier? (examples: oxygen, carbon dioxide, alcohol and most anesthetic agents)

lipid soluble substances

3 things that can cause the breakdown of the blood brain barrier

inflammation, trauma and toxins

clear colourless liquid that carries oxygen, glucose and other needed chemicals from the blood to neurons and neuroglia and removes wastes and toxic substances produced by the brain and spinal cord.

cerebrospinal fluid

4 ventricles found in the brain?

2 lateral, 1 third and 1 fourth

specialized networks of capillaries in the walls of the ventricles (site of CSF production)?

choroid plexuses

cover the choroid plexus capillaries (in ventrical walls). form cerebrospinal fluid from blood plasma by filtration and secretion.

ependymal cells

fingerlike extensions of arachnoid mater that gradually reabsorb cerebrospinal fluid

arachnoid villi

4th ventricle -\>central canal of spinal cord -\>subarachnoid space -\> around brain and spinal cord

cycle of csf

CSF drains primarily into a vein called the....

superior sagittal sinus

average CSF volume?

80-150ml

composed of small bundles of myelinated axons (white matter) and small clusters of neuronal cell bodies (grey matter). ascending and descending neurons.

reticular formation

continuation of the spinal cord forming the inferior part of the brain stem

medulla oblongata

all sensory and motor tracts between the brain and spinal cord are contained in the white mater of the?

medulla oblongata

nuclei that regulates the rate and force of the heart beat and blood vessel diameter?

cardiovascular center

nulcei that adjusts basic rhythms of breathing?

medullary respiratory center

nuclei associated with: touch, pressure, vibration and conscious proprioception AND nuclei that control reflexes for: swallowing, vomiting, hiccuping, coughing and sneezing are located here.... AND nuclei associated with nerves 8-12

posterior medulla

located above the medulla and anterior to the cerebellum? contains sensory and motor tracts and nuclei. Helps regulate breathing with medullary respiratory centre. nuclei of origin for nerves 5-8

Pons

connects the Pons to the diencephalon?

midbrain

pair of large tracts in the anterior midbrain containing axons of motor neurons \= conduct impulses from cerebrum to spinal cord, medulla and pons

cerebral peduncles

nuclei of the \_________ contribute to: control of movements, coordinate movements of the head eyes and trunk in response to visual and auditory stimuli. Nuclei of origin for cranial nerves 3+4

midbrain

when stimulated \= consciousness \= state of alert, aware and oriented. Active when waking from sleep.

Reticular activating system

inactivation of this system produces a sleep state: partial consciousness from which you can be aroused.

reticular activating system

main descending (motor) function of the Reticular activating system?

helps regulate muscle tone

major regions of this part of the brain include the: thalamus, hypothalamus and pineal gland

Diencephalon

Composed of grey matter masses (nuclei) and tracts of white matter. Functions: Relays almost all sensory input to the cerebral cortex. Plays a role in maintaining consciousness. Contributes to motor functions.

Thalamus

greatest function is to maintain homeostasis (part of diencephalon). Through: 1) control of ANS, 2)control of pituitary gland and hormone production 3) regulation of emotional and behavioural patterns 4) regulation of eating and drinking 5) control of body temperature 6) regulation of circadian rhythms and states of consciousness

Hypothalamus

part of endocrine system that: secretes melatonin hormone a powerful antioxidant that promotes sleep and sets biological clock

Pineal gland

1) smooths and coordinates contractions of skeletal muscles 2) regulates posture and balance 3) may play a role in cognition and language

cerebellum

cerebellum divided into (2)

cerebellar hemispheres

consists of a surface of grey matter with an interior of white matter resembling the branches of a tree

cerebellum

bundles of axons that attach cerebellum to the brain stem

cerebellar peduncles

\_____________ gives us the ability to read, write and speak. Make calculations, compose music, remember and create.

Cerebum

folds in cerebrum from rapid grey matter development in fetus called?

gyri

deep grooves between gyri in cerebrum called?

fissures

shallow grooves in cerebrum called?

Sulci