CTO Quiz 3: Study Buddy

Question 1

What are some synonyms for “cell body” of a neuron?

Answer 1

soma, parikaryion

Question 2

What does a neuron look like?

Answer 2

cell body with large euchromatic (stains lightly, DNA unpacked) nucleus and lots of rER in cytoplasm (nissl), has long axon and smaller dentrites projecting outward

Question 3

Where do axons arise from in the neuron?

Answer 3

axon hillock

Question 4

Where does protein synthesis take place in the neuron?

Answer 4

in nissl substance, within cell body, less in dendrite, almost never in axon

Question 5

What is found in greater abundance in the cytoplasm axon than in the neuronal body?

Answer 5

neurotubules and neurofilaments

Question 6

How are things transported in axon?

Answer 6

kinesin motors moving outwards on microtubules (anterograd, toward synapse), dynein motors moving inwards (retrograde, towards cell body)

Question 7

What is the difference between fast and slow axoplasmic transport?

Answer 7

speed of transport dependent on the objects affinity for motor molecules and how long they stay bound

Question 8

What is transported within the axon?

Answer 8

proteins (no synthesis in axon), cytoskeletal elements, organelles such as mitochondria and vesicles

Question 9

What is the general speed of fast and slow axoplasmic transport?

Answer 9

slow- 0.2- 0.4 mm/day

fast- 20-400 mm/day

Question 10

What are synaptic vesicles?

Answer 10

vesicles that are released when Ca enters the axon triggered by the action potential
membrane bound and contain neurotransmitters to act on post-synaptic cell

Question 11

What are the pre-synaptic and post-synaptic densities?

Answer 11

the densities are made up of proteins
pre-synapse includes proteins for docking and release of vessicles
post-synapse includes receptors and associated regulatory molecules/enzymes

Question 12

What is an action potential and what ions are responsible for it?

Answer 12

action potential is a propagating depolarization of a cell membrane
caused by influx of Na into the cell through voltage gated ion channels

Question 13

Why do action potentials move in one direction and not “double back” on themselves?

Answer 13

after the voltage gated Na channels open to allow Na influx, they subsequently close and then are deactivated for a period of time (absolute refractory period) so that the action potential cannot go backwards

Question 14

What ion is responsible for the processes that result in the release of neurotransmitter from the nerve terminal?

Answer 14

depolarization of nerve terminal results in opening voltage gated Ca channels to let Ca into cell, which causes docking and fusion of synaptic vesicles (release of neurotransmitter)

Question 15

How do neurotransmitters cross the synapse?

Answer 15

diffusion

Question 16

What are the possible effects of a neurotransmitter on the post-synaptic cell?

Answer 16

can be stimulatory (increase the chance of generating an action potential) or inhibitory (decrease change of generating action potential) or
modulatory (having some longer term effect on the post synaptic cell through second messengers)

Question 17

What are the 3 mechanisms for termination of action of neurotransmitter?

Answer 17

1) enzymatic degredation
2) reuptake
3) diffusion away

Question 18

What are the 2 broad types of receptors for neurotransmitters?

Answer 18

1) ionotropic- ligand gated ion channels

2) metabotropic- activate enzymes in post-synaptic cell through second messenger systems

Question 19

What is a Schwann cell?

Answer 19

cell in PNS that wraps around axons to form myelin sheath
derived from neural crest cells
can also simply encase axons but not wrap around (unmyelinated axons)

Question 20

What is the process of myelination of peripheral nerve fibers?

Answer 20

Schwann cells interact with specific signals (glycoproteins) on the axon and on won membranes to wrap plasma membrane around axons
gap junctions interconnect the wraps of myelin to allow communication within sheath

Question 21

What transmembrane proteins would be high in concentration at the node of Ranvier?

Answer 21

voltage gated ion (Na) channels

Question 22

What is the function of the myelin sheath?

Answer 22

to increase speed of action potential via salutatory conduction
action potentials only need to be generated at the nodes of Ranvier and conduction is very rapid in between

Question 23

What is the range of conduction speeds from unmyelinated axons to the fasted myelinated axons?

Answer 23

fast- 100m/sec

slow- <1 m/sec

Question 24

What are the connective tissues sheaths of the peripheral nerves?

Answer 24

epineurium (surrounds entire nerve)
perineurium (surrounds individual fascicles of nerve)
endoneurium (surrounds each axon)

Question 25

What are the two general types of ganglia?

Answer 25

sensory and autonomic

Question 26

What are satellite cells?

Answer 26

surround ganglion cells (PNS) to maintain proper environment

Question 27

Where is the gray matter in CNS?

Answer 27

deep in the brain, near ventricles or on the surface (cortex)

Question 28

What are the four types of glia found in CNS and which type is not derived from neuroepithelial cells?

Answer 28

astrocytes ependymal cells oligodendrocytes microglia- derived from mesoderm and migrate to CNS

Question 29

What are the basic functions of each of the types of glial cells?

Answer 29

astrocytes- maintain propper ionic concentrations; support neurons with trophic factors and particpate in clearing excess neruotransmitter; induce endothelial cells in capillaries in brain matter to form tight junctions- blood brain barrier ependymal cells- line ventricles; specialized ependymal cells (choroid plexus cells) cover capillaries in brain cavity (ventricles)- blood-CSF barrier oligodendrocytes- send projections to axons in CNS to form myelin sheaths microglia- phagocytotic, involved in immune response

Question 30

What is the blood brain barrier and what actually comprises the barrier?

Answer 30

barrier between capillaries in brain and the brain matter capillaries have tight junctions and few pinocytotic vesicles, have transport molecules for tihngs to get into the brain, while blocking thgns that wuld be harmful comprised of epithelial cells, acted on by astrocytes

Question 31

What is the blood-CSF barrier and what actually comprises the barrier?

Answer 31

choroid plexus epithelial cells form barrier between blood in the fenestrated capillaries of the choroid plexus and CSF tight junctions between these epithelial cells that only allow certain molecules to pass into CSF

Question 32

What is the basic structure of a blood vessel

Answer 32

tunica adventia (outermost layer) tunica media tunica intima (innermost layer) lumen

Question 33

What is the tunica intima?

Answer 33

innermost layer of blood vessel comprised of simple squamous endothelial cells (and basement membrane) and inner elastic lining (in arteries)

Question 34

What is the tunica media?

Answer 34

middle layer comprised of smooth muscle cells and fibroeleastic connective tissue more prominent in arteries than veins

Question 35

What is the tunica adventitia?

Answer 35

outtermost layer, consists of mostly connective tissue that blends with the surrounding CT layers more prominent in veins may have an external elastic lamina separating it from the tunica media (esp in muscular arteries)

Question 36

What are vaso vasorum?

Answer 36

small blood vessels that supply blood vessel wall

Question 37

What are nervi vascularis?

Answer 37

nerves that supply the blood vessels | can consist of sensory and autonomic nerve fibers

Question 38

Where is the circulatory system the slowest?

Answer 38

capillaries- more area

Question 39

What are the features of elastic arteries and where would you find them?

Answer 39

stretchable, found in large arteries clsoe to heart such as aorta contain lots of smooth muscle and layers of elastic fibers

Question 40

What are the features of muscular arteries?

Answer 40

have prominent internal elastic lamina in their intima media with 4-40 layers of smooth muscle include small and medium arteries which have progressively less elastic fibers and smooth muscle as artery becomes smaller

Question 41

What is the structure of arterioles and what do they do?

Answer 41

1-4 layers of smooth muscle | contribute most to TPR

Question 42

What are metarterioles?

Answer 42

smallest arterioles (only one layer of smooth muscle) that regulate flow into capillary beds via contraction of smooth muscle cells that can close off the flow to capillaries

Question 43

What is the structure of capillaries?

Answer 43

very small only one RBC can flow through at a time single layer of endothelial cells surrounding a basement membrane may have a pericyte within basement membrane which has contractile functions

Question 44

What are the types of capillaries?

Answer 44

1) continuous- most common, endothelial cells uninterupted, transport acress these cells by diffusion, specific transport or pinocytotic vesicles 2) fenestrated- small pores within the endothelial cells, may or may not have pore diaphrams, allow freer transport 3) discontinuous- large pores/gaps, usually incomplete basement membrane (most common lining for sinusoids)

Question 45

What are the functions of endothelial cells

Answer 45

transfer of nutrients and waste to and from interstitial space active in inflammatory response have anti-thrombogenic (prevent clots) functions produce and secrete several vasoactive substances including vasoconstrictors (endothlin) and vasodialators (NO)

Question 46

What are the functions of post-capillary venules?

Answer 46

gas exchange | site where most WBCs leave blood stream to enter tissues

Question 47

What is the structure of veins?

Answer 47

has tunica intima, tunica media (both thin and not very prominent) and tunica adventitia (more prominent) has bicuspid valves to prevent backflow some smooth muscle in media

Question 48

What is the structure of the heart wall?

Answer 48

inside to outside: | endocardium (intima), myocardium (media, muscle cells), epicardium (adventitia)

Question 49

What are Perkinje fibers and what do they look like?

Answer 49

modified cardiac muscle cells that are larger and stain paler than regular cardiac cells specialized to conduct impulses from atria toward apex of heart run in a sub-endocardial position

Question 50

What is the structure of lymphatic vessels?

Answer 50

thin walls, lined by endothelium with connective tissue casing share some similarities with veins in that they have weak walls with valves

Question 51

What is hematocrit and what is a normal value?

Answer 51

% of RBC in blood | normal ~ 35-49%

Question 52

What is the normal hemoglobin concentration?

Answer 52

13.5- 17.5 gm/100mL

Question 53

What is a normal erythorcyte count?

Answer 53

4-5 million/ microliter | 4.3- 6.2 for males; 3.8- 5.5 for females

Question 54

How long do RBCs live?

Answer 54

~120 days

Question 55

What are the molecules that control the shape of RBCs?

Answer 55

spectrin and actin make RBCs biconcave- maximizes surface area

Question 56

How large in diameter are RBCs?

Answer 56

~7.2 micrometers

Question 57

What are reticulocytes and about how many should there be in the blood?

Answer 57

immature erythrocytes containing some ribosomes (basophilic stippling) have this appearance about a day after release from bone marrow about 1% of RBCs are reticulocytes

Question 58

About how many WBCs are there in a microliter of blood?

Answer 58

~4,000- 10,000 leukocytes

Question 59

What are the types of WBCs?

Answer 59

granulocytes- neutrophils, eosinophils and basophils | agranulocytes- lymphocytes and monocytes

Question 60

What are azurphilic granules?

Answer 60

lysosomes | present in all granulocytes, can also be seen in monocytes

Question 61

What is the function of neutrophils?

Answer 61

phagocytotic cells that react to areas of inflammation and infection and destroy pathogens (esp bacteria)

Question 62

Which granulocytes are most abundant, which are the least?

Answer 62

PMNs (neutrophil) are most abundunt | basophils very rare

Question 63

What is the appearance of the nucelus of neutrophils?

Answer 63

``` multiple lobes (one may be a Barr body) often called polymorphonuclear leukocytes ```

Question 64

What is the appearance of a PMNs that is newly released from bone marrow?

Answer 64

nucleus has a horse shoe shape- called a band or stab cell | increased in acute infections

Question 65

What is the appearance and contents of specific granules in eosinophils? What is the importance of these contents?

Answer 65

have bilobed nucleus specific granules have red-orange appearance with cat-eye shape contain and release major basic protein in parasitic infections and allergic reactions

Question 66

What is the appearance of basophils?

Answer 66

contain dark blue/black specific granules that contain heparin, histamine and slow reacting substance of anaphylaxis (similar to mast cells)

Question 67

What is the smallest leukocyte? Largest?

Answer 67

lymphocytes are smallest (2nd most abundant and most important in immune reactions) monocytes are the largest (differentiate into macrophages in tissues, are pat of mononuclear phagocytotic system)

Question 68

What is the most abundant formed blood element?

Answer 68

RBCs most abundant, followed by platelets (100-300,000 /microLiter)

Question 69

What is the appearance of a platelet?

Answer 69

dark staining, disk shaped fragments | no nucleus, just cytoplasm with many layers of membrane and circumferential band of microtubules

Question 70

How long do platelets survive in the blood?

Answer 70

~10 days

Question 71

What is the function of platelets?

Answer 71

induce clotting- cytoplasm contains clot forming and vasoactive substances play role in adhesion and aggregation of endothelial injuries, formation of fibrin clots, retraction of clots (actin, myosin), and lysis of clots (plasmin)