Anatomy & Physiology Exam Study Guide

What is ALS?

ALS also refers to amyotrophic lateral sclerosis- Lou Gehrig disease, destruction of motor neurons and muscular atrophy, also sclerosis (scarring) of lateral regions of the spinal cord, astrocytes fail to reabsorb the neurotransmitter glutamate from the tissue fluid; accumulate to toxic levels, early signs are muscular weakness, difficulty speaking, swallowing, and use of hands, sensory and intellectual functions remain unaffected.

Contractile protein that makes up the thin filaments

Actin

What is anterograde and retrograde in axonal transport?

Anterograde transport: movement down the axon away from the soma. Retrograde transport: movement up the axon toward the soma.

What are the 6 different types of glial cells?

Astrocytes, Oligodendrocytes, Ependymal cells, Microglia, Schwann cells, and Satellite cells

What are the 3 layers of the meninges called? Where does an "epidural" take place and when is it given?

Dura mater, arachnoid mater, and pia mater. The epidural takes place in the dura mater, closest to the skin, and its utilized during childbirth.

What are the layers of the meninges? What order are they in and what are some distinctive features?

Dura mater, arachnoid mater, pia mater. Dura mater- has 2 layers: outer periosteal- equivalent to periosteum of cranial bones; inner meningeal- continues into vertebral canal and forms dural sac around the spinal cord. Cranial dura mater is pressed closely against cranial bones. No epidural space and not attached to bone except around foramen magnum, sella turcica, the crista galli, and sutures of the skull. Layers separated by dural sinuses. Arachnoid mater: transparent membrane over brain surface, subarachnoid space separates it from pia mater below, subdural space separates it from dura mater above in some places. Pia mater: very thin membrane that follows contours of brain, even dipping into sulci, not usually visible without a microscope.

What are fascicles, tracts, endoneurium, perineurium, and epineurium?

Fascicles: nerve fibers gathered in bundles. Tracts: subdivisions of each column. Endoneurium: a thin sleeve of loose connective tissue. Epineurium: bundles of numerous fascicles that constitutes the whole nerve.

What is hyperpolarization?

Hyperpolarization refers to a state where the potential across the membrane is more negative than the resting potential; when it becomes less sensitive and less likely to produce an action potential.

Cylindrical organelles made up of myofilaments and found within the sarcoplasm of the muscle cell

Myofibril

Contractile protein that make up the thick filaments

Myosin

What are mixed nerves?

Nerves that contain both sensory and motor neurons

What neuroglia cells are in the PNS and what cells are in the CNS?

Only the Schwann cells and Satellite cells are in the PNS, the other 4 are in the CNS.

What are pre- and post- synaptic neurons?

Presynaptic neurons may synapse with a dendrite, soma, or axon of postsynaptic neurons to form axodendritic, axosomatic, or axoaxonic synapses. Presynaptic neurons release neurotransmitters. Postsynaptic neurons respond to neurotransmitters sent by presynaptic neurons.

A modified smooth endoplasmic reticulum that surrounds each myofibril and stores Ca2+

Sarcoplasmic reticulum

Enlargement of the SR on either side of the transverse tubules

Terminal cisternae

Making up the T-tubule and two terminal cisternae

Triad

What are the 4 major categories of neurotransmitters?

acetylcholine- in a class by itself, formed from acetic acid and choline. Amino acid neurotransmitters- include glycine, glutamate, aspartale, and y-aminobutyric acid (GABA). Monoamines- synthesized from amino acids by removal of the -COOH group, retaining the - NH2 (amino) group, major monoamines are: epinephrine, norepinephrine, dopamine (catecholamines), histamine, and serotonin. Neuropeptides.

What is the trigger zone?

an axon hillock and the initial segment; plays an important role in initiating a nerve signal. Located in the myelin sheath.

What are anterior/posterior ramus?

anterior: innervates the anterior and lateral skin and muscles of the trunk; gives rise to nerves of the limbs; mixed spinal nerves that connect CNS to anterior side of the body and/or the limbs. Posterior: innervates the muscle and joints in that region of the skin and skin of the back; mixed spinal nerves that connect the CNS to posterior side of the body.

What are ascending and descending tracts?

ascending tracts: carry sensory information up to the spinal cord. Descending tracts: carry motor information down the spinal cord.

What are the 3 functions of the CSF?

buoyancy- allows brain to attain considerable size without being impaired by its own weight, if rested heavily on floor of cranium, the pressure would kill nervous tissue. Protection- protects the brain from striking the cranium when the head is jolted, shaken child syndrome and concussions do occur from severe jolting. Chemical stability- flow of cerebrospinal fluid (CSF) rinses away metabolic wastes from nervous tissue and homeostatically regulates its chemical environment.

Cells branch

cardiac muscle

Has intercalated discs

cardiac muscle

Only found in the heart

cardiac muscle

What is poliomyelitis?

caused by the poliovirus, destroys motor neurons in brainstem and anterior horn of spinal cord, signs of polio include muscle pain, weakness, and lose of some reflexes followed by paralysis, muscle atrophy, and respiratory arrest, virus spreads by fecal contamination of water.

What is a nerve plexus?

complex branched networks of the anterior rami of the cervical, lumbar, and sacral nerves.

What is spina bifida?

congenital defect in which one or more vertebrae fail to form a complete vertebral arch for enclosure of the spinal cord; 1 baby out of 1000, common in lumbosacral region, spina bifida occulta and spina bifida cystica.

What is posterior ganglion?

contains the somas of sensory neurons carrying signals to the spinal cord.

What are the first 6 cranial nerves? what are their names, functions, and is it sensory, motor, or mixed?

cranial nerve 1 (olfactory nerve)- sense of smell and its sensory. Cranial nerve 2 (optic nerve)- provides vison and its sensory. Cranial nerve 3 (oculomotor nerve)- controls muscles that turn the eyeball up, down, and medially, as well as controlling the iris, lens, and upper eyelid and its motor. Cranial nerve 4 (trochlear nerve)- eye movement (superior oblique muscle) and its motor. Cranial nerve 5 (trigeminal nerve)- largest of the cranial nerves, most important sensory nerve of face, divides into 3 divisions: ophthalmic divison-sensory; maxillary divison- sensory; and mandibular divison- missed and cranial nerve 5 is mixed. Cranial nerve 6 (abducens nerve)- provides eye movement (lateral rectus muscle) and its sensory.

Detects the sense of smell

cranial nerve 1 Olfactory (sensory)

Contains visceral sensory neurons whose chemoreceptors detect blood CO2 concentration

cranial nerve 10 Vagus (mixed)

Innervates muscles of the tongue

cranial nerve 12 Hypoglossal (motor)

Transmits visual stimuli

cranial nerve 2 Optic (sensory)

Opens the eye and constricts the pupil

cranial nerve 3 Oculomotor (motor)

Moves the eyes laterally and inferiorly

cranial nerve 4 Trochlear (motor)

Elevates the mandible during chewing

cranial nerve 5 trigeminal (mixed)

Abducts the gaze by turning the eye laterally

cranial nerve 6 Abducens (motor)

Innervates muscles of speech and muscles that move the head

cranial nerve 6 Accessory (motor)

What are the other 6 cranial nerves? what are their names, functions, and are they sensory, motor, or mixed?

cranial nerve 7 (facial nerve)- sensory role in taste and motor role in facial expressions, salivary glands, tear glands, nasal and palatine glands and its mixed. Cranial nerve 8 (vestibulocochlear nerve) - hearing and equilibrium and its sensory. Cranial nerve 9 (glossopharyngeal nerve) - swallowing, salivation, gagging, control of BP and respiration and its mixed. Cranial nerve 10 (vagus nerve)- most extensive distribution of any cranial nerve; major role in control of cardiac, pulmonary, digestive, and urinary functions, swallowing, speech, regulation of viscera and its mixed. Cranial nerve 11 (accessory nerve)- swallowing, head, neck, and shoulder movement and its motor. Cranial nerve 12 ( hypoglossal nerve)- tongue movements for speech, food manipulation, and swallowing and its motor.

Bell's palsy is a disease that can strike without warning and causes weakness and paralysis of facial muscles, usually only on one side. Its cause is not completely understood, although it has been linked to viral infections and even lyme disease. Which cranial nerve is affected by this disease?

cranial nerve 7 (facial)

Innervates the muscles of facial expression

cranial nerve 7 Facial (mixed)

Equilibrium and sense of hearing

cranial nerve 8 Vestibulocochlear (sensory)

Responsible for swallowing movements

cranial nerve 9 Glossopharyngeal (mixed)

What are Schwann cells?

envelope nerve fiber tissues in the PNS. Wind repeatedly around a nerve fiber, produce a myelin sheath similar to the ones produced by oligodendrocytes in CNS, and assist in the regulation of damaged fibers.

What are Oligodendrocytes?

forms myelin sheaths in the central nervous systems. Each arm-like process wraps around a nerve fiber forming an insulating layer that speeds up signal conduction.

What are microtubules?

guide materials along the axon; motor proteins (kinesin and dynein) carry materials on their backs while they crawl along the microtubules.

What is meningitis?

inflammation of the meninges; serious disease of infancy and childhood, especially between 3 months and 2 years of age. Caused by bacterial and viral invasion of the CNS by way of the nose and throat. Pia mater and arachnoid mater are most often affected. Bacterial meningitis can cause swelling of the brain, enlarging the ventricles, and hemorrhages.

What is a regeneration tube?

is formed by Schwann cells, basal lamina, and the neurilemma near the injury.

What are Ependymal cells?

lines internal cavities of the brain, secretes and circulates cerebrospinal fluid; clear liquid that bathes the CNS. Cuboidal epithelium with cilia on apical surface.

Compare local potentials and action potentials.

local potentials are disturbance in membrane potential when a neuron is stimulated. Neuron response-> dendrite-> soma-> axon-> synaptic knobs. When neuron is stimulated by chemicals, light, heat, or mechanical disturbance opens the Na+ gates and allows Na+ to rush to the cell, Na+ inflow neutralizes some of the internal negative charge, voltage measured across the membrane drifts toward zero, depolarization-case in which membrane voltage shifts to a less negatice value, Na+ diffuses for short distance of the inside of the plasma membrane producing a current that travels toward the cells trigger zone-this short range change in voltage is called a local potential. Differences between local potentials from action potentials are graded-vary in magnitude with stimulus strength (stronger stimuli open more Na+ gates.) Are decremental- get weaker the farther they spread from the point of stimulation (voltage shift caused by Na+ inflow diminishes rapidly with distance. Are reversible- when stimulation occurs, K+ diffusion out of cell returns the cell to its normal resting potential. Can be either excitatory or inhibitory (some neurotransmitters make the membrane potential more negative- hyperpolarize it- becomes less sensitive and less likely to produce an action potential.

What are Anaxonic neurons?

many dendrites, but no axon; help in visual processes.

What are Astrocytes?

most abundant glial cells in the CNS, cover the entire brain surface and most nonsynaptic regions of the neurons in the gray matter of the CNS, diverse functions. Forms a supportive framework of nervous tissue, have extensions (perivascular feet) that contact blood capillaries that stimulate them to form a tight seal called the blood-brain barrier, converts - blood glucose to lactate and supply this to the neurons for nourishment, nerve growth factors secreted by astrocytes promote neuron growth and synapses formation communicate electrically with neurons and may influence synaptic signaling, communicate electrically with neurons, regulate chemical composition of fluid tissue by absorbing excess neurotransmitters and ions, astrocytosis or sclerosis- when the neuron is damaged, astrocytes form hardened scar tissue and fill space formerly occupied by the neuron.

what is anterior root?

motor output out of spinal cord; nerves coming off the anterior region of the spinal cord containing only somatic and visceral motor signals from the CNS to skeletal muscles and gland cells.

What is kinesin?

motor proteins in anterograde transport

What is dynein?

motor proteins in retrograde transport

What are the different types of neurons?

multipolar, bipolar, unipolar, and anaxonic

What are nodes of Ranvier and internodes?

nodes of Ranvier are gaps between segments. Internodes are myelin covered segments from one gap to the next.

What are Multipolar neurons?

one axon and multiple dendrites, most common, most neurons in the brain and spinal cord.

What are Bipolar neurons?

one axon and one dendrite; olfactory cells, retina, inner ear.

What is the blood-brain barrier?

protects capillaries throughout the brain tissue. Consists of tight junctions between endothelial cells that form the capillary walls, astrocytes, endothelial cells can exclude harmful substances from passing to the brain tissue while allowing necessary ones to pass.

What is the blood- CSF barrier?

protects the brain at the choroid plexus. Tight junctions are absent from ependymal cells elsewhere; important to allow exchange between brain tissue and CSF.

What are the two types of refractory period and when do they occur?

refractory period is the period of resistance to stimulation. 2 phases: absolute refractory period and relative refractory period. Absolute refractory period: no stimulus of any strength will trigger AP, from action potential to RMP. Relative refractory period: only especially strong stimulus will trigger new AP, until hyperpolarization ends.

What is the process of regeneration of nerve fibers?

regeneration of a damaged peripheral nerve fiber can occur if its soma is intact and at least some neurilemma remains. Regeneration of damaged nerve fibers in the CNS cannot occur at all.

What is rostral and caudal?

rostral - toward the forehead. Caudal- toward the spine.

What is cerebral aqueduct?

runs through the midbrain and connects third to fourth ventricle.

Plasma membrane of a muscle cell

sarcolemma

What is the difference between Schwann cells and Oligodendrocytes?

schwann cells and oligodendrocytes both have very similar roles, but Schwann cells are found in the PNS and oligodendrocytes are in the CNS. Schwann cells spiral repeatedly around a single nerve fiber while oligodendrocytes are anchored to multiple nerve fibers. Oligodendrocytes also can't migrate around any one f them like Schwann cells can. Schwann cells in PNS have no cytoplasm between the membranes, neurilemma- thick outermost coil of myelin sheath contains nucleus and most of its cytoplasm external to neurilemma is basal lamina and a thin layer of fibrous connective tissue- endoneurium. In CNS- oligodendrocytes reaches out to myelinate several nerve fibers in its immediate vicinity, must push newer layer of myelin under the older ones so myelination spirals inward toward nerve fibers, nerve fibers in CNS have no neurilemma or endoneurium.

What are the classifications of the different types of nerve fibers?

sensory (afferent) nerves- carry signals from sensory receptors to the CNS. motor (efferent) nerves- carry signals from the CNS to muscles and glands. mixed nerves- consists of both afferent and efferent fibers, conducts signals in two directions. Both sensory and motor fibers can be described as somatic or visceral, general or special. visceral fibers innovate blood vessels, glands, and viscera. somatic fibers innervate skin, skeletal muscles, bones, and joints. general fibers innervate more localized organs in the head, including the eyes, ears, olfactory and taste receptors, and muscles of chewing, swallowing, and facial expressions.

What is posterior root?

sensory input to spinal cord; nerves coming into the posterior region of the spinal cord that contains only sensory signals from the PNS to the spinal cord.

What is denervation atrophy?

shrinkage of paralyzed muscle when nerve remains disconnected; muscle loss due to loss of nerve contact by damaged nerve.

What are Unipolar neurons?

single process leading away from the soma, sensory from skin and organs to spinal cord.

Always has multiple nuclei per cell

skeletal muscle

Long, unbranched cells

skeletal muscle

Striated and voluntary

skeletal muscle

What are rootlets?

small groups of axons sending information to the periphery

What are Microglia?

small, wandering macrophages formed from white blood cells called monocytes. Thought to perform a complete checkup on the brain tissue several times a day. Wander in search of cellular debris to phagocytize.

Involuntary

smooth and cardiac muscles

Found in walls of hollow internal organs

smooth muscle

Lacks striations

smooth muscle

spindle-shaped

smooth muscle

How do unmyelinated vs. myelinated nerves, large vs. small diameter, nerve fibers work?

speed at which a nerve signal travels along a nerve fiber depends on the dimeter of the fiber and the presence or absence of myelin. Conduction speed: small, unmyelinated fibers- 0.5-3.0 m/sec; small, myelinated fibers- 3-15.0 m/sec; large, myelinated fibers-up to 120 m/sec. Signal conduction occurs along the surface of a fiber. Large fibers have more surface area and conduct signals more rapidly, myelin further speeds signal conduction. Slow signals supply the stomach and dilate pupil where speed is less of an issue. Fast signals supply skeletal muscles and transport signals for vision and balance.

What are the layers in a nerve?

spinal cord communicates with the rest of the body by way of spinal nerves. Nerve- a cordlike organ composed of numerous nerve fibers (axons) bound together by connective tissue. Mixed nerves contain both afferent (sensory) and efferent (motor) fibers, composed of thousands of fibers carrying currents in opposite directions, nerves of peripheral nervous system are ensheated in Schwann cells, forms neurilemma and often myelin sheath around the axon, external to neurilemma, each fiber is surrounded by basal lamina and then a thin sleeve of loose connective tissue- endoneurium. Fascicles, perineurium, epineurium, and blood vessels penetrate connective tissue coverings; nerves have high metabolic rate and need plentiful blood supply.

What is choroid plexus?

spongy mass of blood capillaries on the floor of each ventricle.

What are Satellite cells?

surround the neurosomas in ganglia of the PNS. Provide electrical insulation around the soma and regulate the chemical environment of the neurons.

How many spinal nerves are there?

there are 31 pairs of spinal nerves. 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

How many ventricles and where can they be found?

there are 4 ventricles within the brain. Two lateral ventricles: one in each cerebral hemisphere. Third ventricle: single narrow medial space beneath corpus callosum. Fourth ventricle: small triangular chamber between pons and cerebellum.

What is interventricular foramen?

tiny pore that connects to the third ventricle.

What is axonal transport?

two way passage of proteins, organelles, and other material along the axon.

What is saltatory conduction?

voltage gated channels need for APs, fast Na+ diffusion occurs between nodes. The nerve signal seems to jump from node to node is the definition.