KAAP309 - Unit 2: Nervous System EXAM

Define mastication

chewing

What are the 5 tastes?

sweet, sour, salty, bitter, umami

What is the pathway through the ear (auditory)?

Auricle/pinna -> auditory canal -> tympanic membrane -> malleus -> incus -> stapes -> oval window -> scala vestibuli -> cochlear duct -> scala tympani -> secondary tympanic membrane->vestibulocochlear nerve->temporal lobe

What would happen to a sound if its cycles/second increased?

We would perceive it as getting higher

What would happen to a sound if its amplitude increased?

We would perceive it as getting louder

Explain the process by which tastants activate gustatory receptors

Ions come into contact with the taste pores and their gustatory hairs. The ion then binds to the taste receptor in the taste bud

What are the components of the outer ear?

auricle (pinna), external auditory canal, tympanic membrane

What are the components of the middle ear?

tensor tympani muscle, tympanic membrane malleus, incus, stapes, auditory tube

What are the components of the inner ear?

cochlea, macula, otolithic membrane, crista ampullaris, vestibule, semicircular canals

What is the structure and function of teeth?

-Structure: 4 layers (enamel, dentin, cementum, tooth pulp)
-Function: grinding, cutting, and crushing up food

What is the structure and function of salivary glands?

-Structure: exocrine glands
-Function: help moisten food, as food needs to be dissolved in water to be tasted, protecting teeth, protect digestive tract, produce saliva

What is the function of macula in equilibrium?

-Function: monitors position of head relative to its vertical position

What is the function of crista ampullaris in equilibrium?

-Function: sense acceleration and deceleration of the head

What are the four types of lingual papillae?

filiform, fungiform, vallate, foliate

What is the structure of filiform papillae?

Tiny spikes found mostly on the middle of the tongue, does not contain any taste buds

What is the structure of fungiform papillae?

Mushroom-shaped bumps concentrated at the tip and sides of tongue

What is the structure of vallate papillae?

Large circular bumps that form a V towards the back of the tongue

What is the structure of foliate papillae?

Two parallel ridges on the sides of the tongue

What is the structure and function of the organ of Corti/spiral organ?

-Structure: fluid-filled structure with hair cells and a basilar membrane
-Function: convert sounds into electrical impulses

What do lamellar corpuscles sense?

deep pressure, stretch, tickle, vibration

What do hair receptors sense?

light touch, movement of hairs

What do tactile corpuscles sense?

light touch, texture

What do tactile discs sense?

Light touch, pressure

What do free nerve endings sense?

temperature, pain

Most encapsulated nerve endings are what kind of receptor?

Mechanoreceptors

What is the taste pathway?

Taste buds -> CN 8, 9, 10 -> foramina -> solitary nucleus (medulla) -> thalamus (some go to hypothalamus and amygdala) -> gustatory cortex (insula)

What is the auditory pathway? (start from the inner ear)

organ of corti -> CN 8 -> medulla (both sides) -> cochlear nucleus and superior olivary nucleus (pons) -> inferior colliculus (midbrain) -> thalamus (binaural) -> bilateral auditory cortex (temporal lobe)

How are action potentials generated in the organ of Corti?

Hair cells bend to movements in the perilymph and stimulate the dendrites of the spiral organ, which transduces the sound into neural impulses

How is vibration amplified in the ear?

The ossicles (malleus, incus, stapes) amplify it

True or false: loudness is related to frequency

False

True or false: pitch is related to basilar membrane location

True

# of neurons in ascending tracts?

3 (1st, 2nd & 3rd order )

What kind of information do ascending tracts carry ?

general sensory information

where do ascending tracts start?

in a dorsal root ganglion

Where do ascending tracts finish ?

in the somesthetic cortex (postcentral gyrus)

What are the 2 kinds of ascending tracts?

Dorsal White Column (DCML) & Spinothalamic "anterolateral system"

What is the order of the Dorsal White Column Tract?

Dorsal Root Ganglion -> (1st order) → medulla (synapse) -> (2nd order & decussation ) → thalamus (synapse) -> (3rd order) → Somesthetic Cortex

What is the order of the Spinothalamic Tract?

Dorsal Root Ganglion (1st order) -> Dorsal Horn of the Spinal Cord (synapse) → (2nd order & decussation ) -> Thalamus (synapse) -> (3rd order) -> Somesthetic Cortex

where do descending tracts start?

Primary motor cortex (precentral gyrus )

# of neurons in descending tracts?

2 (upper motor neuron & lower motor neuron)

What kind of information do descending tracts carry ?

general motor information

where do descending tracts end?

skeletal muscle

what are the kinds of descending tracts?

Lateral corticospinal tract & Anterior corticospinal tract

What is the order of the Lateral corticospinal tract?

(upper motor neuron) precentral gyrus → medulla (decussates at pyramids) → lateral funiculi → ventral horn (lower motor neuron, also in ventral horn, place of synapse)- > skeletal muscle

What is the order of the Anterior corticospinal tract?

(upper motor neuron) precentral gyrus → medulla → lateral funiculi → ventral horn, decussates (lower motor neuron, also in ventral horn, place of synapse) → skeletal muscle

What does decussation?

decussation is the crossing over of neurons, it usually occurs in or right after the medulla in the spinal cord * pyramids of decussation in the medulla

What section of the spinal cord does the DCML enter?

gracile fasciculus & cuneate fasciculus

where does the DCML decussate?

medulla (medial lemniscus )

Where does the lateral corticospinal tract decussate?

in the medulla

Where does the anterior corticospinal tract decussate?

in the spinal cord

what does the autonomic NS control?

Visceral reactions of the body

what does the somatic NS control?

the voluntary motions of the body

what are the 2 divisions of the autonomic nervous system?

sympathetic and parasympathetic nervous system

What does the sympathetic nervous system do?

arouse the body and prepare for fight, flight, or freeze

what do does the parasympathetic nervous system do?

relax the body and prepare for rest and digestion

What neurotransmitters does the sympathetic nervous system utilize?

the adrenergic system utilizes norepinephrine and epinephrine

what neurotransmitters does the parasympathetic nervous system utilize?

the cholinergic system utilizes acetylcholine

Are preganglionic neurons myelinated or unmyelinated?

myelinated

Are postganglionic neurons myelinated or unmyelinated?

unmyelinated

Where the origin of sympathetic NS?

the lateral horns of T1 & L2 (thoracolumbar)

Fiber lengths of Sympathetic Division

short preganglionic and long postganglionic

Neural divergence of the sympathetic division?

extensive

Effects on system in sympathetic division?

often widespread and general

location of ganglia in sympathetic

paravertebral ganglia adjacent to the spinal column and prevertebral ganglia anterior to it

Where is the origin of the parasympathetic NS?

craniosacral (travels through cranial nerves 3, 7, 9, 10) or the splanchnic nerves

where is the location of ganglia in the parasympathetic division?

terminal ganglia near or within the target organs

fiber lengths of the parasympathetic division?

long preganglionic and short postganglionic

neural divergence in the parasympathetic division?

Minimal

effects on the parasympathetic division?

more specific and local

What are the routes of the Sympathetic NS?

Spinal nerve route & sympathetic nerve route

preganglionic neurons travel through which ramus?

pre - white ramus

postganglionic neurons travel through which ramus?

post - gray ramus

Features of the sympathetic nerve route?

travels through the spinal cord (sympathetic trunk) and synapses in the same ganglion level, does a loop through the ramus and then travels to the ganglion

Features of the splanchnic nerve route?

travels through the splanchnic nerve and becomes apart of the splanchnic nerve after the ganglion

What are the routes of the Parasympathetic NS?

Cranial synapse and sacral synapse

Where does the Cranial synapse interact?

Cranial synapse that travels through the cranial nerves (III, VII, IX, X)

Where does the Sacral synapse interact

travels the anterior rami from the pelvic splanchnic nerves

Chromaffin cells?

cells of the adrenal medulla, they sit on the kidneys and are apart of the sympathetic ns. and are attached to the splanchnic nerve

How many connections do somatic reflexes have?

direct connection to the target cells

How many connections do autonomic reflexes have?

2 step pathway consisting of a preganglionic and post ganglionic neurons

Describe sympathetic autonomic reflexes.

anterior root nerve between T1 and L3

Describe the parasympathetic nervous system.

anterior root nerve in the craniosacral region

Describe adrenergic receptors and neurons (neurotransmitters)

sympathetic ns, alpha is excitatory, beta is inhibitory, primarily uses norepinephrine, and epinephrine

Describe cholinergic receptors and neurons (neurotransmitters )

parasympathetic ns and sympathetic ns, muscarinic receptors, uses acetylcholine

muscarinic receptors are on:

muscles and glands

nicotinic receptors are on:

cells of the autonomic ganglia, adrenal medulla and skeletal muscle

what type of neuron/receptor belongs to both the parasympathetic and sympathetic

nicotinic

how do muscarinic receptors impact different types of muscle?

excitatory towards smooth muscle, inhibitory towards cardiac muscle

is cholinergic receptors and neurons exclusively for the parasympathetic nervous system?

no! they are found in both but mostly sympathetic

How do the cranial bones and the vertebral column protect the CNS?

The cranial bones serve as protection for the brain, while the vertebral column serves as protection for the spinal cord.

List the 3 meninges from superficial to deep

1. dura mater
2. arachnoid mater
3. pia mater

Dura Mater - location and structure (layers, sinuses, folds) in CNS

Location: most superficial meningeal layer located between bone of skull/vertebrae and arachnoid mater

Structure: 2 layers (periosteal and meningeal), dural venous sinuses (space between layers containing blood vessels), 3 dural folds (falx cerebri, falx cerebelli, tentorium cerebelli)

Arachnioid Mater - location and structure in CNS

Location: middle meningeal layer located between dura mater and pia mater

Structure: transparent + contains largest blood vessels of the cerebral surface

Pia Mater - location and structure in CNS

Location: deepest meningeal layer located between the cerebral cortex and arachnoid mater

Structure: thin layer completely adhered to the brain; follows gyri and sulci and has blood arteries penetrating the cerebrum (also: filum terminale is an extension of the pia mater)

dura mater - brain vs spinal cord + reason for difference

brain: meningeal layer + periosteal layer
spinal cord: ONLY meningeal layer

reason: function of the periosteal layer is to provide a tubular sheath-like covering for the cranial nerves as they pass through the different foramina of the skull; as soon as the cranial nerves exit the foramen, the periosteal layer fuses with the epineurium of nerves

dural venous sinuses - location, structure, function

Location: in between the periosteal and meningeal layer of the dura mater

Structure: large space containing veins within the dural sheath; space within dural sheath is created by the collective effort of the dural folds (falx cerebri, falx cerebelli, tentorium cerebelli)

Function: manages blood return from the brain to the normal circulatory system

cranial dural septa (folds) - structure and function

falx cerebri: tough-crescent shaped wall; separates 2 cerebral hemispheres

falx cerebelli: smaller fold; separates 2 cerebral hemispheres through the cerebellum

tentorium cerebelli: crescent shaped fold that stretches like a roof over the posterior cranial fossa; separates cerebrum from the cerebellum

epidural space - location and potentiality

Location: above the dura and below the cranium

Potentiality: potential space in the brain (would become real only in instances of bleeding) but a real space in the spinal cord

*sidenote: site of injection for birth and surgeries

subdural space - location and potentiality

Location: below dura mater and above arachnoid mater

Potentiality: potential space

subarachnoid space - location and potentiality

Location: below arachnoid mater and above pia mater

Potentiality: real space