Human Phys exam 3

Identify the structure indicated by the arrow

1 = fascicle
2 = muscle cell (myofiber)
3 = myofibril

Which of the following best describes the main proteins of the thick & thin filaments of skeletal muscle?

Thin filament is actin; thick filament is myosin

This graphic most likely represents …

neuromuscular junction

what is a motor unit?

a motor neuron & the muscle fibers connected to it

action potential

electrical signal that travels across SR & down T-tubules

calcium release

calcium leaves SR and binds to troponin C

troponin activation

calcium binds troponin C which causes tropomyosin to move away from myosin-binding sites on actin

cross-bridge formation

myosin binds to myosin-binding sites, myosin head attaches to actin and forms cross-bridges

relaxation

calcium is pumped from cytosol back into SR by SERCA using ATP

describe the power stoke & the role of calcium in cross-bridge cycling?

the power stroke is the bending of the myosin head that pulls actin toward the center of the sarcomere; calcium binds to troponin, moving tropomyosin and exposing myosin-binding sites on actin

the structures shown here are ….
Which structure will likely generate the greatest force (tension) once the muscle is stimulated to contract?

the structures shown here are sarcomeres
structure B will likely generate the greatest force (tension)

The 3 curves in the plot show total tension, passive tension, and active tension. What are the values in grams of passive (preload) tension, active tension, and total tension when the muscle length is 60 cm?

A
Preload = 100
active tension = 200
total tension = 300

In this myogram of tension vs time, what is occurring at 1 & 2?

1 : summation
2: tetanus

these images show skeletal muscle of mice that lack the protein myostatin. The wild-type mice are normal controls. Myostatin directly limits the growth & size of myofiber cells (muscle fibers). What is likely happening in the muscle of animals that are missing myostatin?

their muscles are unusually large because myofiber growth is no longer inhibited by myostatin

muscle cells get atp from broth aerobic & nonaerobic pathways (t/f)?

true c

creatine phosphate provides a phosphate for …

atp formation

during rest & for mild exercise, muscles get energy via …

fatty acid break down

during moderate exercise, or heavy exercise, muscles get energy via …

glucose release

which of the following best describes a typical type 1 skeletal muscle fiber?

oxidative, high capillary density, many mitochondria, slow twitch

factors that determine muscle force (strength)

number of muscle fibers recruited
thickness (cross-sectional area) of individual muscle fibers
frequency of motor neuron stimulation

what is muscle atrophy and what are some common causes of this condition?

muscle atrophy is a decrease in muscle size and strength, often caused by disuse, aging, or certain medical conditions

what is oxygen debt in the context of skeletal muscle physiology?

the extra oxygen required by muscles during intense exercise to compensate for the oxygen deficit incurred during anaerobic metabolism

which of the following best described the difference between muscle spindles and golgi tendon organs?

muscle spindles detect muscle length, while golgi tendon organs detect muscle tension

what is the primary neural mechanism underlying the knee-jerk reflex?

transmission of sensory signals from the muscle spindle to the spinal cord, eliciting a reflex response

what does image 1 and 2 represent? What is the main function if the structure indicated by the star?

image 1: single-unit smooth muscle
image 2: multi-unit smooth muscle
starred structure: to allow small molecules or ions to pass between cells

what is a major source of calcium that initiates contraction of smooth muscle?

extracellular fluid

what triggers calcium release from the sarcoplasmic reticulum in cardiac muscle?

calcium influx through calcium channels

contraction is voluntary and controlled by somatic motor neurons (which type of muscle)

smooth muscle

contraction is involuntary & can be initiated by hormones, stretch, or autonomic signals (which type of muscle)

skeletal muscle

contraction is regulated by proteins that block or expose myosin-binding sites in actin

regulated by troponin & tropomyosin

contraction is controlled by an enzyme-activated calcium-binding protein that triggers myosin activity

regulated by calcium binding to calmodulin

Name 10 things that may be found in blood

1. water

2. red blood cells

3. white blood cells

4. platelets

5. plasma

6. electrolytes (K+, Na+)

7. urea

8. hormone (insulin, testosterone)

9. cholesterol

10. glucose

what is the general function of monocytes & netrophils?

phagocytic
monocyte = agranulocyte; netrophils = granulocytes

what is the general function of lymphocytes?

make and release anti-bodes (only B lymphocytes), immune response
agranulocyte

what is the general function of basophils?

release anticoagulants (heparin) for blood clotting
granulocyte

what is the general function of eosinophils?

kill pathogens & parasites
granulocyte

what is the general function of platelets?

form fibrin (clotting), release serotonin for vasoconstriction
fragments of cells, formed elements, no nucleus

what is the general function of erythrocytes?

red blood cells
transport O2 & CO2

Match the blood type with its characteristic: type A

Type A:

has anti-B antibodies
has A antigens

Match the blood type with its characteristic: type B

type B:
has B antigens
has anti-A antibodies

Match the blood type with its characteristic: type AB

Type AB:
has both A and B antigens
has neither anti-A or anti-B antibodies
universal recipient

Match the blood type with its characteristic: type O

type O:
universal donor
has neither A or B antigens
both anti-A & anti-B antibodies

1

superior vena cava

2

pulmonary artery

3

right atrium

4

tricuspid AV valve

5

right ventricle

6

chordae tendineae

7 `

papillary muscles

8

inferior vena cava

9 (its cut off but its the line at the top)

aorta

10

left atrium

11

bicuspid valve (AV)

12

aortic semilunar (SL) valve

13

pulmonary semilunar (SL) valve

14

papillary muscles

Complete the blood flow pathway

vena cava (1) —>
right atrium —>
tricuspid (2) —>
right ventricle (3) —>
pulmonary SL valve —>
pulmonary arteries (4) —>
lungs —>
pulmonary veins (5) —>
left atrium —>
bicuspid valve —>
left ventricle (6) —>
aortic SL valve (7) —>
aorta —>
body/ tissue cells (8) —>
vena cava

oxygen binds to ____ in red blood cells

hemoglobin

during ____, the AV valves are open and the SL valves are closed. The SA node begins depolarization of atria.

ventricular filling

during _____, the outflow vessels SL valves are open

ventricular ejection

during _____, the ventricular myocardium depolarizes and contracts, also, both AV and SL valves are closed

isovolumic contraction

during ______, the ventricular myocardium is repolarizing and both AV and SL valves are closed.

isovolumic relaxation