Bio 2160 Crousillac Exam 4

What is an individual muscle cell?

Muscle Fiber

What are the clusters of proteins within each muscle cell?

Myofibrils

A membrane has (single/multiple) nuclei

Multiple (multinucleated)

Muscles cells (do/do not) divide in adulthood.

do not

When muscle tissue dies, it (does/does not) grow back

does not

Neuron that innervates a muscle cell.

Motor Neuron

What is the name of the endoplasmic reticulum in muscle cells?

Sarcoplasmic Reticulum

What is stored in the sarcoplasmic reticulum?

Calcium

Where are T-Tubules found?

in the muscle membrane & runs deep into the myofibrils

Where is the motor end plate found?

Muscle Cell Membrane

Explain the process of moving your finger...

1. Acetylcholine gets released from motor neurons then binds to receptors on the end plate (depolarization).
2. Channels open: Sodium comes in, Potassium goes out.
3. End plate potential develops action potentials.

All contractions happen (at once/in a sequence)

in a sequence

Thick and thin filaments come in contact with each other at _______.

crossbridges

What two things do all muscle contractions require?

Calcium & ATP

What keeps myosin from being in contact with actin?

Troponin

What moves tropomyosin around?

-calcium binding site, actin binding site, tropomyosin binding site

Troponin

What covers up the binding site on actin when muscles relax?

-extends along thin filaments, masks myosin binding site in absence of calcium

Tropomyosin

How does a cramp occur?

By involuntary skeletal muscle contraction

Name the regulatory proteins:

Tropomyosin & Troponin

Made up of two strands of actin that form double helix

Thin Filaments

Made up of myosin dimers bound together at tails, binding sites on heads (crossbridges) for actin, ATPase site

Thick Filaments

______ gives permission for contractions to occur.

Calcium

Name the steps of muscle contraction:

1. Motor Neuron Action Potential
2. End plate potential (excitation)
3. Increase in muscle cell calcium levels
4. Troponin and Tropomyosin conformation change
5. Crossbridge cycling to sliding filaments (CONTRACTION)

Calcium binds to ______ to move ______ out of the way, which causes a contraction.

Troponin/ Tropomyosin

Another name for calcium channels in the sarcoplasmic reticulum

Ryanodine Receptors

What is the job of DHP receptors?

detect action potentials and when they do, they change shape and pull open calcium channels (Ryanodine receptors) so calcium goes out of SR into the muscle cell.

-voltage sensor

The majority of calcium needed in a muscle cell comes from ______ receptors.

DHP

When ATP binds to myosin, myosin now has a ______ affinity for actin.

Low

When ATP binds to myosin, the muscle contraction (starts/stops) and myosin lets go of actin.

stops

When attached to ADP, myosin has a _____ affinity for actin.

High

When myosin is attached to ADP, actin binds to it, forming a ________ between myosin and actin.

Cross-Bridge

What causes the myosin head to close causing the power stroke?

Release of an inorganic phosphate

You need more ______ to relax muscles.

-this is why dead bodies are stiff

ATP

Name the ways muscle contraction is terminated:

1. Motor neuron input terminates
2. End plate potentials terminate
3. High myoplasmic calcium concentration shuts SR calcium channels
4. Active calcium uptake through SERCA pumps on SR move calcium from cytoplasm to SR.
5. Calcium dissociated from troponin
6. Tropomyosin covers myosin binding sites on actin

The most work that a single action potential can produce.

-The mechanical response or change in force/tension (measured in grams) of an individual muscle fiber, motor unit, or whole muscle to a single action potential

Twitch

Muscle-generated force causes muscle shortening and lifts a load.

-load must be less than or equal to muscle tension.
-Ex: grabbing a chair and actually lifting it. (moving the load)

Isotonic Twitch

Muscle-generated force but does not shorten (load/force opposing muscle shortening is greater than muscle tension) the muscle can't shorten.

-Ex: pushing against a wall...it doesnt not move even though you are exerting force on it.

Isometric Twitch

The amount of time it takes for a fiber to respond after you've told it to respond

-time of thinking about it until it actually happens

Latent Period

Contain slow myosin

-hydrolyzes ATP to ADP and P slower, myosin head cocking is slower

Slow Twitch Fibers

Contain fast myosin

-hydrolyzes ATP to ADP and P faster, myosin head cocking is faster

Fast Twitch Fibers

T/F: Skeletal muscles can contain slow twitch fibers, fast twitch fibers, or both.

True

T/F: Conditioning and training muscle can teach the muscle to respond more quickly.

True

Anaerobic generation of ATP

Glycolytic

Aerobic generation of ATP

Oxidative

Fibers that have a high concentration of glycolysis enzymes

Glycolytic

Fibers that have a low concentration of glycolysis enzymes

Oxidative

Fibers that contain a lot of mitochondria

Oxidative

Fibers that contain myoglobin (oxygen storage molecule)

Oxidative

Fibers that are large in diameter

Glycolytic

Fibers that have less blood flow and are lighter in color

Glycolytic

What type of exercise increases oxidative fiber capacity?

-conversion of some glycolytic fibers into oxidative fibers

Low Intensity (yoga, pilates)

What type of exercise increases glycolytic capacity & decreases oxidative capacity?

-conversion of some oxidative fibers into glycolytic fibers
-fatigue is caused by lactic acid buildup
-depletion of ACh

High Intensity (out of breath)

T/F: smooth muscle has no sarcomeres but crossbridge cycling still occurs.

True

Calcium for smooth muscle comes from (inside/outside) the cell.

Outside

Calcium for skeletal muscle comes from (inside/outside) the cell.

Inside (sarcoplasmic reticulum)

In smooth muscle, actin and myosin connect to connective tissue at ______ ______.

Dense Bodies

Calcium binds to ______ in smooth muscle.

Calmodulin

Calmodulin binds and activates what enzyme in smooth muscle allowing cross bridges to form?

MLCK: Myosin Light Chaine Kinase

What shuts off smooth muscle contraction?

Inactivation of myosin by phosphatases, which remove phosphate group from myosin light chain.

What would be the consequence if phosphatases stopped being produced in a cell?

smooth muscle would stay contracted too long

Name the 3 components of the cardiovascular system

Blood, Blood Vessels, Heart

What are the 2 ways to increase pressure in the heart?

1. Add more blood
2. Contract the chamber of the heart

What are the 2 main components of blood?

Blood cells & plasma

What are the components of blood cells?

Erythrocytes
Leukocytes
Platelets

Red blood cells
-carry oxygen bound to hemoglobin (contains iron)

Erythrocytes

White blood cells
-Mediate immune responses

Leukocytes

Cell "fragments"
-aid in blood clotting

Platelets

Liquid portion of blood-yellow part
-mostly water and proteins, antibodies, and ions.

Plasma

Blood vessels that transport blood away from the heart (3)

Arteries, arterioles, capillaries

Blood vessels that transport blood to the heart (2)

Veins & venules

Pulmonary refers to:

Lungs

Systematic refers to:

everything except the lungs

Largest artery and blood vessel in the body & carries blood from the left ventricle to everywhere in the body.
-high pressure

Aorta

T/F: blood flows from the pulmonary circuit to the systematic circuit in the body.

True

In systematic capillary beds, ______ leaves the blood and ______ enters.

O2 enters
CO2 leaves

Chambers are opened and closed by ______ differences between chambers.

pressure

Heart valves allow (unidirectional/bidirectional) blood flow.

Unidirectional

Valves that separate atria and ventricles.
-mitral and tricuspid valves

Atroventricular valves

Valves that separate ventricles and arteries.
-aortic (left) and pulmonary (right) valves

Semilunar valves

T/F: when a ventricle is relaxed it is because atrial pressure > ventricular pressure

-this causes the atrioventricular valve to open

True

T/F: when a ventricle contracts it is because ventricular pressure > atrial pressure

-this causes the atrioventricular valve to close

True

T/F: when a ventricle contracts it is because ventricular pressure > aortic pressure

-this causes the semilunar valve to open

True

T/F: when a ventricle relaxes it is because aortic pressure > ventricular pressure

-this causes the semilunar valve to close

True

Which ventricle is most muscular because it pumps blood to the entire body?

Left Ventricle

_____ branches and carries blood to all organs & tissues in the systematic circuit.

Aorta

If you stop breathing, the build up of _____ kills you before the lack of oxygen does.

CO2

Blood is (oxygenated/deoxygenated) in the organ capillary beds.

deoxygenated

Deoxygenated blood travels back to the heart through the ______ & ______ into the right atrium.

Superior & Inferior Vena Cavas

Pressure is almost always (higher/lower) in the vena cavas than the heart.

higher

Blood in the RIGHT atrium travels through _____ to get to the right ventricle.

tricuspid valve

A healthy heart has:

A. fewer beats and less blood leaving

B. fewer beats and more blood leaving

C. more beats and less blood leving

D. more beats and more blood leaving

B. fewer beats and more blood leaving

-this is because your heart does not have to work as hard.

The only artery to carry deoxygenated blood

Pulmonary artery

Blood in the right ventricle flows through the ______ into the pulmonary artery.

pulmonary semilunar valve

The only oxygenated vein in the body

pulmonary vein

After blood is oxygenated in the lungs, it travels to the ______ through the pulmonary vein.

Left atrium

From the left atrium, blood goes through the _____ into the left ventricle.

Bicuspid / Mitral Valve

Meaning "the heart tells itself to contract"

-the heart contracts without neural input

Myogenic

RHYTHM of the heartbeat is due to activity of ______ & ______.

-pace of the heart

Pacemaker Cells & Conduction Fibers

FORCE of heartbeat is due to activity of _______.

-force of contraction

Contractile Cells

Action Potentials are (longer/shorter) in skeletal muscle cells than cardiac muscle cells.

Longer