Neuroscience: Nervous System Organization, Neuron Structure, and Brain Protection

What is a ganglion?

A cluster of neuro cell bodies in the PNS.

What is a nucleus in the nervous system?

A cluster of neuron cell bodies in the CNS.

What is the conduction velocity in a larger heavily myelinated axon compared to a smaller unmyelinated axon?

Faster due to saltatory conduction and reduced resistance.

What is the significance of the blood-brain barrier?

selective transport of substances, protects from toxins and pathogens, maintains a table envronemnt

What are commissural tracts?

Tracts that connect corresponding areas in two hemispheres.ex. cor[us callosum

What are projection tracts?

Tracts that connect the cerebrum to lower brain areas and spinal cord. desciending and ascending ex. pyramidal

What are association tracts?

Tracts that connect areas within the same cerebral hemisphere. acruate fasiculus

What is the longitudinal fissure?

It divides the cerebrum into left and right hemispheres.

What functional areas are exclusively in the frontal love

primary motor cortex, premotor cortex, brocas area, frontal eye field

What are the functions of the motor cortex?

Controls voluntary movements of skeletal muscles.

What is the function of the premotor cortex?

Controls learned motor skills that are repetitive.

What is the function of Broca's area?

Speech production.

What is the function of the frontal eye field?

Controls extrinsic eye muscles.

What happens when the left frontal eye field is damaged?

difficulty moving eyes to the right.

What are pyramidal cells and where are they located?

Large neurons in the primary motor cortex.

Where is Wernicke's area typically located?

Left temporal lobe.

What is the function of Wernicke's area?

Language comprehension and expression.

What is the arcuate fasciculus?

It connects Broca's and Wernicke's areas.

What is Broca's aphasia?

Difficulty producing speech

What is Wernicke's aphasia?

Difficulty understanding speech and using correct words.

Name the 3 main cerebral basal nuclei.

Caudate nucleus, Putamen, Globus pallidus.

What is the function of the caudate nucleus?

Plans voluntary movement and learned behaviors.

What is the function of the putamen?

Regulation of body movements and motor skills.

What is the function of the globus pallidus?

Regulates muscle tone and inhibits unwanted movement.

What causes Parkinson's disease?

Degeneration of dopamine-producing neurons in the substantia nigra.

Why is L-DOPA used instead of dopamine in the management of Parkinson's disease?

L-DOPA can cross the blood-brain barrier and is converted to dopamine in the brain.

What is the function of the lateral geniculate nucleus?

Visual relay center.

What is the function of the medial geniculate nucleus?

Auditory relay center.

What are the functions of the red nuclei?

Regulates limb flexion.

What is the function of the substantia nigra?

Dopamine releasing neurons that modulate activity of basal nuclei.

Where are the corpora quadrigemina located?

Midbrain.

What is the function of the superior colliculi?

Acts as the visual reflex centers.

What is the function of the inferior colliculi?

Acts as the auditory reflex centers.

Why can trauma to the brainstem be fatal?

It contains medulla oblongata and pons which controls fucntions essential for life

Which cerebellar lobe cannot be viewed on the surface of the cerebellum?

Flocculonodular lobe.

What is the major function of the cerebellum?

Processes info from cerebral motor areas, visual equillibrium, coordinated voluntary skeletal movements, maintencance of balance

What type of paralysis occurs when the spinal cord is transected above the cervical enlargement?

Quadriplegia.

What type of paralysis occurs when the spinal cord is transected below the cervical enlargement?

Paraplegia.

What is the difference between paralysis caused by damage at the precentral gyrus and damage at the spinal cord?

Precentral gyrus damage results in hemiplegia.

What are the parts of the PNS?

Afferent (sensory) division and Efferent (motor) division.

What causes dilation of the pupils?

Activation of the sympathetic division.

What causes constriction of the pupils?

Activation of the parasympathetic division.

What causes bronchodilation?

Activation of the sympathetic division.

What causes generalized vasoconstriction?

Activation of the sympathetic division.

What are the three major parts of the eye?

Eye wall (3 layers), Humors, Lens (biconvex)

What are the two parts of the fibrous layer of the eye?

Sclera and Cornea

What is the function of the pupil?

controls how much light enters the eyes

What are the functions of the aqueous humor?

Supplies nutrients and O2 to the lens and cornea, carries away waste, maintains pressure for support

What is myopia?

Near sightedness; eyeball too long, distant objects focused in front of the retina

What is hyperopia?

Farsightedness; eyeball too short, light from close objects focused behind the retina

What is the trichromatic theory of vision?

Several colors are seen depending on how or which of the three types of cones are activated

What is the pathway of light through the eye?

cornea, aqueous humir pupil, lens, votrous humor, retina (ganglion, bipolar photoreceptors)

What is the function of the maculae in the vestibule?

Equilibrium receptors that respond to the pull of gravity and head position

What is the organ of Corti?

Located on the basilar membrane, involved in detecting sound vibrations

Does damage to hair cells lead to permanent hearing loss?

Yes, they are specialized sensory receptors that detect sound vibrations

What determines loudness and pitch of sound?

Loudness is determined by amplitude and intensity; pitch is determined by frequency

What is the function of the cochlear nerve?

Carries auditory information from the cochlea to the brainstem

Will damage to the left temporal lobe cause hearing loss in one ear or both?

Both ears, because auditory pathways project bilaterally

What type of cells are the olfactory cells and why are they considered unique in humans?

Bipolar neurons; they can regenerate throughout life.

What are the two criteria a chemical must meet for olfactory processing to occur?

Volatile (airborne) and be dissolved in mucus.

Axons of which neurons form the olfactory nerve?

Axons of bipolar neurons.

Axons of which neurons form the olfactory tract?

Axons of mitral cells from the olfactory bulb.

What is the role of the mammillary bodies in the processing of olfaction?

limib systemA: inducing the amygdala, responsible for the emotional and autonimic responses to odors

Name the two types of cells in a taste bud. What type of cell is the gustatory cell?

Gustatory cells (chemoreceptors) and basal cells (modified epithelial cells).

Name the types of papillae that contain taste buds.

Fungiform, Vallate, Foliate.

Name the gustatory relay center and location

Ventral posterior medial nucleus of thalamus.

What is an endocrine gland?

A ductless gland that secretes hormones into the bloodstream.

What is the difference between a hormone and a neurotransmitter?

Neurotransmitters are released into synaptic clefts; hormones are released into extracellular fluid.

Define negative feedback mechanism as it pertains to the actions of hormones.

A hormone's effects reduce or stop further hormone release to maintain homeostasis.

Name and discuss the 3 major stimuli for the release of hormones.

hormonal, humoral, and neural (nerve fiber)

Name and discuss the 3 classes of hormones

Peptide/protein hormones (made of amino acids), Steroid hormones (derived from cholesterol), Biogenic amine hormones (derived from tyrosine).

What are target cells for a hormone?

A target tissue for a hormone expresses accessible functional receptors that the hormone binds to.

Discuss the characteristics of hormone receptors.

receptors are globular protein, w high specificity

intracellular vs, membrane receptors

intracellular binds w steroid, membrane receptors bind w peptide/protein and biogenic amide because they cant cross the lipid bilayer

Name and discuss the 4 types of hormone interactions with receptors. Can agonism result in the hyperfunction of a hormone?

classical, paracrine, autocrine, juxtacrine

5 hormonal interrelationships

agonism, antagonism, permissiveness, cooperativity, synergism

Is the posterior pituitary considered an endocrine gland

Depends on the definition of an endocrine gland: if you say it releases hormones, then yes, if you say an endocrine Synthesizes then no

Name the seven hormones synthesized by the hypothalamus that travel by the portal system into the anterior pituitary. Give one function of each hormone.

Thrytropin release hormone, corticoptropin release hormone, gonadotropin release hormone, growth homrone releasing hormone, somatastatin, prolactin releasing factor, dopamine

What does calorgenic mean

it regulates the basal mtabolic rate

What type of pancreatic cells release insulin?

Beta cells of pancreatic islets.

What type of pancreatic cells release glucagon?

Alpha cells of pancreatic islets.

Will high levels of cortisol cause hypoglycemia or hyperglycemia? Does cortisol act like insulin or glucagon?

Hyperglycemia; acts like glucagon.

What are the stimuli for aldosterone release?

Low blood Na+ and high blood K+.

If a hormone is released in response to low Na+ and high K+ levels in the blood, will this hormone act by stimulating Na+ excretion and K+ reabsorption?

No; it stimulates Na+ reabsorption and K+ secretion.

example of a type A nerve fiber

motor neuron

example of type B nerve fiber

preganglionic autonomic fiber

example of type C nerve fiber

postganglionic autonomic fibers that innervate smooth muscle pain fibers

septum palllucodum

connects the two lateral ventricles

interventricular foramen

conencts the lateral ventricles tot he third ventricle

where is the fourth ventricle located

brain stem

why is the thalamus the gateway to the cerebral cortex

relay station for sensory inputs to the cerebral cortex

name the 2 pigmented nuclei in the midbrain

red nuclei and substantia nigra

the axons of dopaminergic nuerons in the substantia nirga project to waht structures of the cerebrum

the basal nuclei

Spinal epidural sheath

single layered dura matter

conus medullaris

cone shaped ends of medulla oblongata

filum terminale

fibrous extensions of the pia mater extending from the conus, vertically anchros the spinal cord

denticulate ligamnets

anchors spinal cord laterally

epidural space

contains veins and fat

central canal

core of spinal cord

describe the parts of the afferent division

mechanoreceptors, chemorecepotrs, and photoreceptors