Biol 307 Human Physiology Chapter 12 and 14

Striated Muscle

Muscles that appear to have alternating light and dark bands; it also includes skeletal and cardiac muscle

Tendon

Connective tissue that attaches skeletal muscle to the bone

Origin

End of the muscle that is attached closest to the trunk or to the more stationary bone

Insertion

More distal or more mobile attachment

Antagonistic Muscles

Flexor-extensor pairs of muscles attached to the same set of bones

Fascicle

A group of muscle fibers sheathed in connective tissue bundled together

Sarcomere

A contractile unit of myofibril

Myofibril

Highly organized bundles of contractile and elastic proteins that carry out the work of contraction

Sarcoplasmic Reticulum

a form of modified endoplasmic reticulum that wraps around each myofibril like a piece of lace

T-tubule or Transverse Tubules

Invaginations of the muscle fiber membrane associated with the sarcoplasmic reticulum

Myosin

a motor protein with the ability to create movement

Actin

A globular protein (G-actin) that polymerizes to form thin filaments

Crossbridge

Connection formed when mobile myosin heads bind to actin molecules in muscle

Power Stroke

when myosin crossbridges swivel and push the actin filaments toward the center of the sarcomere.

Cardiac Output

The amount of blood pumped by one ventricle in a given period of time

Venous Return

The amount of blood that enters the heart from venous circulation

Myoglobin

a red oxygen-binding pigment with a high affinity for oxygen

Motor Unit

The basic unit of contraction in an intact skeletal muscle

Skeletal, Cardiac, and Smooth Muscle location and function

Skeletal muscle- Attached to the bone of the skeleton and are responsible for controlling body movement

Cardiac muscle- In the heart and moves blood through the circulatory system

Smooth muscle- Primary muscles of internal organs and tubes. Its primary responsibility is to move material into, out of, and within the body.

A muscle fiber is simply…

a muscle cell

Thin filaments are made of…

actin (recognize)

Thick Filaments are made of…

Myosin (recognize)

Muscle cells generally use a combination of what to produce ATP

Glucose and Fatty Acids

Which process in muscle contraction requires ATP?

The power stroke process

Smooth muscle does not have sarcomeres because…

it needs to be able to contract when stretched

Smooth muscle generally contracts without

nervous system input but can be regulated by the autonomic nervous system

Capillary

the microscopic vessels where blood exchanges material with the interstitial fluid

Artery

Blood vessels that blood away from the heart

Septum

A central wall that divides the heart

Resistance

The tendency of the cardiovascular system to oppose blood flow

Autorhythmic Cells

cardiac cells that spontaneously and rhythmically depolarize and fire action potentials

Vein

Blood vessels that return blood to the heart

Pulmonary Artery and Veins

Artery-Blood vessel that carries low oxygen blood from the right heart to the lung

Veins-Blood vessel that carries well-oxygenated blood from the lung to the left heart

Electrocardiogram ( ECG)

A recording of the summed electrical events of the cardiac cycle

Superior and Inferior Vena Cava

Superior- The veins that form the upper part of the body

Inferior- The veins that form the lower part of the body

Vasoconstriction

A decrease in blood vessel diameter

Vasodilation

An increase in blood vessel diameter

Pericardium

The connective tissue sac that encloses the heart

Myocardium

Cardiac Muscle

Systole

The time during which the muscle contracts

Diastole

The time during which the muscle relaxes

End Diastolic Volume

The maximum volume the ventricles can contain after ventricular relaxation (diastole)

Stroke Volume

the amount of blood ejected out of the heart per beat

What is the order of blood flow?

Heart>Arteries>Arterioles> Capillaries>Venules> Veins> Heart

What is the pathway blood flows in the heart

Right atrium>Right ventricle> Pulmonary artery> Lungs> Pulmonary vein>Left atrium> Left ventricle> Aorta

Recognize that blood flows down its…

pressure gradient and the rate of blood flow is proportional to the blood pressure difference between two places

The relationship between blood vessel radius…

and resistance is a 4th power relationship

1 refers to

Right ventricle

2 refers to

Left Ventricle

3 refers to

Coronary Artery and Vein

4 refers to

Right Atrium

5 refers to

Auricle of left atrium

6 refers to

Pulmonary Artery

7 refers to

Aorta

8 refers to

Superior Vena Cava

What are some real life examples of important changes in blood vessel diameter?

• Exercising can lead to venous constriction and a cascade of effects leading to increased stroke volume

• Anxiety or stress can can also influence venous constriction

• Dehydration can also influence blood flow and decrease stroke volume

Explain and identify the function of heart valves and why an incompetent heart valve is bad?

Heart Valves ensure the blood moves in and out of the heart in one direction and prevent blood from moving backwards. If one of the valves is incompetent then blood pressure and heart rate can be influenced along with sympathetic nervous system activity.

Why are cardiac muscles connected by gap junctions?

Gap Junctions connect cardiac muscles resulting in fast depolarization from cell to cell, allowing for heart muscle cells to contract almost simultaneously

Explain how heart cells spontaneously generate action potentials?

The action potentials spontaneously happen in the heart’s pacemaker cells because of the calcium leak channels. The AP’s flow through the gap junctions and to the muscle contractile cells

What does the S-T wave represent?

The ventricles are ejecting blood into the arteries

What does the P wave represent?

The depolarization of the atria

What do the QRS waves represent?

the QRS complex represents the depolarization of the ventricles, which causes the ventricles to contract and eject the blood in them.

Explain the events of the cardiac cycle?

1. The heart is at rest and the atria and ventricles are relaxed allowing for blood to fill the heart

2. Atrials will contract and systole

3. Ventricles will contract and systole

4. Ventricles will eject the blood, pushing it upwards

5. The ventricles will relax and only keep a certain amount of blood in the ventricles (ESV)

How do you calculate cardiac output

Cardiac Output= Stroke Volume x Heart Rate or bpm x stroke volume

What factors normally affect venous return?

1) Contraction or compression of veins returning blood to the heart

2) Pressure changes in the abdomen and thorax during breathing

3) Sympathetic Innervation of veins

Troponin

Protein that binds to calcium and tropomyosin

Tropomyosin

Large protein on actin filament that myosin attaches to for a contraction or myosin pulling actin

Ryanodine Receptor (RyR)

Gates that keep calcium within the sarcoplasmic reticulum and allows for calcium to exit onto troponin

Summation

Smooth movements caused by multiple action potentials shot off to complete multiple contractions

Tetanus

Recruitment

Pacemaker Potential

Cyclic depolarizations of smooth and cardiac muscles that always reach threshold

What are the steps to a muscle contraction?

Somatic motor neurons will be released and attached to ligand gated channels. Those channels will activate an action potential in the T tubules, that will open the calcium gated channels in the sarcoplasmic reticulum. The released calcium will lead bind to troponin which will then bind to tropomyosin. Tropomyosin will cause a shape change that allows myosin to bind to thin actin filaments. The power stroke occurs by myosin using ATP to move the actin filaments. Finally a full contraction occurs

Excitation-Contraction Coupling

Acetylcholine is released by motor neurons and binds to nicotine receptors cascading into a skeleton muscle action potential leading to contraction

What is the difference between slow twitch vs fast twitch muscles?

Slow twitch use more aerobic respiration; oxidative, more mitochondria, and contains more myoglobin making the fibers dark red

Fast twitch uses more anaerobic or glycolytic respiration, less mitochondria, and is paler in color

The longer the sarcomere or muscle fiber is at the start of constriction…

the greater the tension up until the maximum

Example of smooth muscle

Ocular muscles- accommodation

Reproductive muscles- in the uterus to squeeze out children or support bladder

Urinary muscles- Squeeze out waste

Summation and Tetanus

In order to keep calcium levels high, firing multiple action potentials can lead to a smooth movement called tetanus. This happens to a single muscle fiber

Recruitment

With a muscle carrying more weight, that requires motor neurons to recruit more muscle fibers to have more force to accomodate for the added weight

Arteriole

The smallest arteries and site of variable resistance in the circulatory system

Venule

Small vessels where blood flows into veins

Endothelium

The inner lining of all blood vessels

Angiogenesis

The process in which new blood vessels form after birth

Coronary Heart Disease

Blood flow to the myocardium is decreased by fatty deposits in the lumen of the coronary arteries

Mean Arterial Pressure

The average pressure in your arteries overtime; diastolic pressure + 1/3 pulse pressure

Peripheral Resistance

how much space there is for blood flow in the blood vessels

Baroreceptor

Stretch sensitive mechanoreceptors

Fenestrated Capillary

Capillaries that have large pores to allow for high volumes of fluid to pass rapidly between the plasma and interstitial fluid

Atherosclerosis

Hardening of the arteries when fatty deposits form inside arterial blood vessels

Blood flow is directed to different tissues by…

constricting and dilating arterioles

What is the purpose of the kidneys with blood pressure?

If the blood volume is too high the primary responsibility of the kidneys to remove the excess water in the blood to prevent a high blood pressure.

What happens when the arterioles dilate or constrict and what causes it to happen.

The sympathetic nervous system would dilate the arterioles resulting in increased blood flow and decreased blood pressure. The parasympathetic nervous system would constrict the arterioles resulting in decreased blood flow and increased blood pressure.

Where are fenestrated capillaries found and why are they found there?

They are primarily found in the kidney and the intestine because of the required exchange of blood and tissues.

Where is the slowest and fastest blood flow in the body?

The slowest blood flow is in the capillaries and the fastest blood flow is in the arteries. The capillaries having slow blood flow prevents any dangerous contents from entering the blood, tissues, and heart

what are major functions of the lymphatic system?

1. returning fluid and proteins filtered out of the capillaries to the circulatory system

2. picking up fat absorbed at the small intestine and transferring it to the circulatory system

3. serving as a filter to help capture and destroy foreign pathogens