BIO 118 Unit 4 Exam

cardiovascular transport

movement of things through through the blood stream

external respiration

exchange of gases between lungs (atmosphere) and blood; diffusion, concnetration gradient

internal respiration

Exchange of gases between cells of the body and the blood; diffusion, concentration gradient

bulk flow

The movement of a fluid due to a difference in pressure between two locations.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Trace the pathway of airflow during inhalation or during exhalation

Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli

Trachea

Allows air to pass to and from lungs; lets air through from bulk flow and can constrict or dilate depending on how much o2 is needed, lined with smooth muscles and have mucus secreting cells

bronchus

one of the two tubes that connect the lungs with the trachea; lets air through from bulk flow but can also constrict or dilate depnding on how much o2 is needed by the body. Lined with smooth muscles. Have mucus screteing cells, split into 2 from the trachea

Resistance

How easy/hard it is to move something through. Larger radius means less resistance and smaller radius means more resistance.

ciliated cells

can catch dust and microbes and move them out of the breathing system; have little hair like projections that move in a direction to expell debris and stuff that gets trapped in the mucus of the airway.

How does smoking affect ciliated cells?

Smoking causes damage to cells and kills mitochondria. When they are dead the ATP powered cilated cells are unable to move.

goblet (mucous) cells

make mucus to trap debris and gets moved out by cilated cells in the airway. When more things are added or sticking, there is more mucous production due to these environmental irritants.
- Asthma causes the increase in mucous cells
- Decrease in cells caused by dehydration

Alveoli

Tiny sacs of lung tissue specialized for the movement of gases between air and blood; site of o2 diffusion into the blood stream.
- Thin cells + Increases SA/V ratio = Easier to diffuse
- Mucous should NOT be present because it blocks the diffusion site of your lungs

What dilates the airways?

During fight or flight response, sympathetic nervous system; Needs more o2 for the body

What constricts the airways?

Increase resistance during the parasympathetic system; Doesn't need as much o2

Which regions of the airways has the biggest effect on resistance to airflow?

Bronchi; They are the smaller tubes and are the ones that constrict and dilate the most; have the largest effect on amount of o2 you get in the body

How does radius affect resistance?

- When the radius increases (dilates) = less resistance
- When radius decreases (constrict) = more resistance
- Exponentially decreasing graph

How do we bring air into our lungs? Describe the equation for air flow.

- Negative pressure (pressure gradient) causes air to enter lungs
- Equation represents an exponential decrease

Why is air flow called bulk flow?

Air flow is bulk because it is powered by pressure gradient instead of concentration gradient (diffusion).
- Down a pressure gradient, wants to go towards the one with less pressure

Why does the flow of air stop at the end of inhalation or exhalation?

Inhalation: atmosphere has more pressure, alveoli has less pressure, air goes into the alveoli
Exhalation: atmosphere has less pressure, alveoli has more pressure, air goes out into the atmosphere
- Flow stops because it equalizes pressure between both

vital capacity (VC)

The total volume of air that can be exhaled after maximal inhalation

How do you calculate vital capacity?

Tidal volume + inspiratory reserve volume + expiratory reserve volume OR total lung capacity - residual volume

residual volume (RV)

Amount of air remaining in the lungs after a forced exhalation

Why isn't residual volume ever exhaled?

It never truly collapses because it helps hold the alveolis open so that it is easier to inflate later. Also it can never fully be compressed out since we have the body limits of compression in the ribcage.

dead air volume

Amount of air in respiratory passageways, and not in the alveoli

How does does dead air volume (in the airways) affect the gases in the lungs?

Some of the air becomes old air and is not fresh. If you don't take as deep of a breath you will keep breathing in old air over and over again (air with more co2 and less o2)

respiratory minute volume (RMV)

The amount of air moved into and out of the respiratory system each minute;
- Respiratory rate times tidal volume
- It is better to have a larger respiratory minute volume

How does changing the depth of a breath affect CO2 in the blood?

You want to take very deep breaths and not shallow ones because shallow breaths produce most of the air old air from the dead space in lungs. This means it is not saturated with oxygen and so it is harder to get the oxygen the body needs.

partial pressure (PO2)

- each pressure of gas is independent of other gases
- reflects the amount of oxygen gas dissolved in the blood
- Higher altitude = less Po2 (linear decrease)

total air pressure

- sum of the pressures from individual gasses
- because water vapor is a highly variable gas in space/time, it can contribute a significant amount to total air pressure

Explain how & why oxygen & carbon dioxide partial pressures differ between atmospheric air & air in the alveoli.

- Oxygen is more rich and dense in the atmosphere and co2 is rich and dense in the blood when it is at the lungs
- Oxygen is more rich and dense in the blood versus co2 which is rich and dense in the tissue
- Partial pressures will diffuse and match the pressure of the higher one; that is how gas exchange works

Negative Feedback Loop for Low O2 Level

regulated by the hormone erythropoietin, increases red blood cell production to bring the body back into homeostasis

Negative Feedback Loop for High CO2 or H+

Hypoventilation; chemoreceptors detect and respond and controls repiratory control center which increases ventilation which then changes the arteial blood composition

Negative Feedback Loop for Low CO2 or H+

Hyperventilation; arterial blood has more o2 less co2, and H+ causes chemoreceptors to detect and respond by changing respiratory control center and ventilation goes down this changes the arterial blood composition

Explain the diffusion of gas in external respiration

Occurs in the lungs between alveoli and the blood.
- O2 enters blood co2 which leaves the blood.
- O2 pressure high in alveoli, co2 pressure high in blood

Explain the diffusion of gas in internal respiration

Occurs in the body between blood and tissues.
- O2 enters tissues co2 which leaves the tissues.
- O2 pressure high in blood, co2 pressure high in tissues

Equilibrium

Equalization of the partial pressures through diffusion; the numbers should match the higher value.

pneumonia

An inflammation of lung tissue, where the alveoli in the affected areas fill with fluid;
- result of bacteria or viruses that enters the lungs
- there is an immune response and the alveolar walls thicken by inflation
- This makes it less stretchy and harder to diffuse o2 and co2 in external respiration and it means there is less ventilation and less respiration tissues due from not enough o2.

Ventricular Diastole

Relaxation of the heart; the blood is coming into the ventricle
- 0.5 seconds
- AV valves are open
- SL valves closed

Ventricular Systole

Contraction of the heart; blood is leaving to pass through the vessels
- 0.3 seconds
- AV valves are closed
- SL valves open

Trace the flow of blood through the heart

1. surperior vena cava
2. right atrium
3. tricuspid valve
4. right ventricle
5. pulmonary valve
6. pulmonary arteries
7. pulmonary veins
8. left atrium
9. mitral valve
10. left ventricle
11. septum
12. aortic valve
13. aorta

Atrial Diastole

Ventricular filling;
- both sides of atrium and ventricles are relaxed
- Blood goes into atrium and the ventricle because the AV valves are all closed
- Flows from the pulmonary vein from the lung into the left
- Flows from the vena cava from the body to the right side

Atrial Systole

The contraction of the atria by which blood is propelled from them into the ventricles;
- the AV valves on both side push the blood into the the ventricles and close to stop back-flow
- The chordea tendinae are the fibers connected to the valves and they help close it to stop back-flow due to pressure

isovolumentric contraction

contraction that occurs when the volume of blood in the ventricles remains constant; pressure in the ventricle starts to build, but there isn't much happening

isovolumetric relaxation

period when all four valves are closed and ventricular blood volume does not change;
- the blood gets to move through the receptive vessel away from the heart and the atrium fills with blood and right now both semilunar valves and AV valves are closed to stop back flow
- Soon the AV valve with open again and blood will enter

Cardiac Output (CO)

measurement of the amount of blood ejected per minute from either ventricle of the heart (heart rate times stroke volume)

Heart Rate (HR)

Number of heart beats per minute

Stroke Volume (SV)

The amount of blood pumped out of the heart with each contraction

Which vessels & heart chambers contain oxygenated blood?

Comes from the lungs, so the left side, left atrium, and left ventricle. Also, the Pulmonary vein and aorta.

Why do we call the heart a double pump?

Because there are two sides of the blood, it pumps both to the lungs and to the body. Each side does something different, so it's a double pump.

How does bulk flow differ from diffusion?

- It is driven by differences in pressure potential, not solute potential
- It occurs in hollow dead cells, not across the membranes of living cells
- It moves the entire solution, not just water or solutes
- It is much faster

Which circuit has higher pressure, the lungs or the body?

- Systemic circuit (left side) because it is going to the body and has a longer travel to go
- Pulmonary circuit (right side) is less pressure because it is going less distance

How is cardiac muscle different from skeletal muscle? How are they similar?

Cardiac muscles: only found in the heart
Differences:
- takes extracellular Ca during contraction
- Can talk to other fibers through depolarization current in gap junctions
- They have intercalated disks with increased SA---they can talk to each other, so a contraction doesn't have to go to each one and can spread out from the signal point of a nerve
- Cardiac muscle is also not straight it is branched; smaller SR

valve prolapse

one or more cusps will protrude in the wrong direction, resulting in back-flow; when the valve is leaky or it has gone the wrong way, it doesn't close correctly any more. Causes Heart murmurs or inefficient heart because of back-flow.

What might you observe in someone with a prolapsed aortic valve?

Not enough blood is getting to the body because does not have enough pressure

What might you observe in someone with a prolapsed right AV valve?

Not enough blood is going to the lungs, s the body will slowly loose its O2 supply.

What causes the heart valves to open or close?

Pressure from the blood forces heart valves to close; change in pressure opens and closes valves
- There are also fibers that hold the valves

fibrous skeleton

Dense connective tissue that forms a structural foundation
- point of insertion for muscle bundles
- electrical insulator between atria and ventricles
- Found outside of the heart; cardiac muscle surrounds - It is between the atriums and the ventricles to stop the conducting signal to interfere between the separate beatings.
- Collagen is what it is made of (cartilage) and is bad at conducting so there is a delayed signal between atrial and ventricular systole

How does pressure in the ventricles change during the cardiac cycle?

When blood goes in ventricle, pressure is low. When blood gets squeezed out, ventricle pressure is high (caused by squeezing).

How does pressure in the atria change during the cardiac cycle?

Atria changes when blood goes in it. It is low when blood is squeezed into the ventricle; pressure is high (caused by squeezing).

What causes heart sounds?

the closing of the valves between the atria and ventricle, and the ventricle and the vessels away from the heart
- Valves help keep the pressure in contraction

EDV

end-diastolic volume; volume of blood in ventricle at the end of diastole
- Larger EDV means more volume per stroke beat of the heart
- More blood movement means mores circulation and more o2 to the body

ESV

end-systolic volume; volume of blood in ventricle at the end of systole

SV

stroke volume; how much blood is ejected per each beat of heart
- Larger SV if you have more blood/more blood cells

cardiac muscle cells

shorter cells, cells branch in chain, 1 nucleus per cell, more myoglobin, more mitochondria, smaller SR, has intercalated discs and gap junctions

skeletal muscle cell

longer cells, cells are straight + long, more than 1 nucleus, less myoglobin, less mitochondria, larger SR, no intercalated discs or gap junctions

Are cardiac muscle cells made of red or white fiber?

Red; it needs a lot of myoglobin since it needs lots of endurance (it is working constantly and so it would need to have a lot of aerobic functions there)

Red fibers

Slow-twitch muscle fibers. They are primarily aerobic and contain many mitochondria and myoglobin.

White fibers

Fast-twitch muscle fibers. They are primarily anaerobic and fatigue more easily than red fibers.
- White fibers are for strength and not endurance

gap junctions

Ion channels for the electrical signals that pass from one cell to another in the heart.
- This allows the contraction to continue on and have a gradient
- It also allows it to beat by itself without a nerve impulse.

What are the benefits of the high surface area at an intercalated disc?

More room on the cell membrane to have ion channels; - Allows more signals to go through at a relatively fast pace
- Also allows cells to tightly bind together.

How does the diffusion of extracellular calcium alter heart contraction strength?

The more calcium that goes in, the harder the contraction of the muscle, and the harder the heart beats.
- The channels can be impacted by the autonomic nervous system

How is calcium returned into the SR after the excitation ends?

Calcium is returned to the SR like normal skeletal muscles; there are calcium pumps that put them back in

conduction cells

Cells that conduct the action potentials through the heart providing an excitatory system that controls the rhythmical beating
- lots of mitochondria, lack actin and myosin
- these cells are found in the middle section of the endocardium (lining) and in cardiac muscle cells

Includes Purkinje Fibers

Myocytes (normal cardiac cells)

Very packed together in the cardiac muscle cell section under the conduction cells
- They actually do the contraction when the electrical signal gets to them

Purkinje fibers

Fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract

Pathway of electrical excitation

SA node ---> atrial muscle ---> AV node ---> AV bundle ---> Purkinje fibers ---> ventricular muscle.
6. ventricular muscle (electrical signal gets to muscle and it contracts from apex towards base since the bundle goes down before branching back up. Allows pump of blood to exit up at the base of heart)

SA node (sinoatrial node)

- PRIMARY pacemaker of the heart
- sets the heartbeat rate
- located in the right atrium
- causes atria to contract

AV node (atrioventricular node)

region of the heart between the right atrium and right ventricle from which electrical impulses spread to the ventricles during a heartbeat

AV bundle

The structure in which the AV node rapidly transmits its signal to the ventricular tissues;
- bundle of His
- goes down the middle through the passageway that is tiny, slows down signal
- left goes to left ventricle and right goes right ventricle

funny current

Process of HCN channels open and sodium (Na+) slowly comes in; the pacemaker current

Predict the speed of depolarization of these parts of the conduction system: SA node, AV node, and Purkinje fibers

- SA is primary pace maker because it has the funny (slow) Na cells that always let in Na until threshold is reached.
SA node is fast, AV node is slower, Purkinje fibers are even slower

What does the AV node do if the SA node is damaged?

Might cause slow heart-beat, AV node might take over as the pace maker node;
- Wouldn't cause immediate death but would have very bad consequences long term

Compare excitation at the SA node to action potentials. What ion channels do they have in common?

SA node: funny (slow) Na+ channels cause action potential;
- Ca and K signal to open ---> Ca opens to let in calcium and cause depolarization ---> at peak, the K finally opens and causes repolarization by letting out K and then it is below threshold

Action Potential (Neuron): graded potential causes action potential;
- Na and K signal to open ---> Na open to let in Na and causes depolarization ---> at peak, the K finally opens and causes repolarization by letting out K and then it is below threshold

Their ion channels are the same: K+ channels

Describe the contraction cycle & the roles of ATP and Ca2+.

Cross bridging, ATP role, and Ca2 role in skeletal muscles is the same in cardiac muscles;
- When signaled by a motor neuron, a skeletal muscle fiber contracts as the thin filaments are pulled and slide past the thick filaments within the sarcomere

SL (semilunar) valves

Separates ventricles & arteries, and it OPENS during systole;
- Prevent blood from flowing from great vessels to ventricles

What is the relationship between blood flow, force (Blood pressure) & resistance?

The more force (blood pressure) the faster the blood flows and the more resistance the slower the blood flows
- Blood Pressure has a linear increase relationship
- Resistance has a decrease relationship

How is resistance affected by vessel radius?

As the radius increases, resistance decreases exponentially. As radius increases, flow exponentially increases;
- Volume flow rate = (pressure difference * radius^4)/ (8/pi viscosity * length)

hydrostatic pressure

the pressure within a blood vessel that tends to push water out of the vessel

Why does pressure fluctuate in arteries?

Due to the elastic recoil from elastic fibers on the walls

Where does the blood pressure drop most rapidly? Where is BP lowest?

Drops more rapidly in the small arteries and arterioles because it is transitioning to capillaries which are single cell diameter blood vessels

BP is the lowest in the veins and right atrium because veins have less pressure and less elastic fibers so they are often collapsed in shape they need to get back into the heart to get pumped

Why blood move down a pressure gradient?

Blood moves down the pressure gradient because it is an illustration of bulk flow: moving from high pressure to lower pressure

systemic circuit

Circuit of blood that carries blood between the heart and the rest of the body;
- They supply the tissues of the body with O2 and collect CO2 from the tissues

pulmonary circuit

Carries blood to the lungs for gas exchange and returns it to the heart;
- They pick up O2 from the lungs and deposit CO2 back out

artery

A blood vessel that carries blood away from the heart;
- pressure reservoirs
- they have more elastic fibers
- more smooth muscles to move the blood along.
- Stretch and recoil a lot and have thick walls.
- Diameter is very fat and radius is large

Arterioles

small vessels that receive blood from the arteries

vein

A blood vessel that carries blood back to the heart;
- the volume reservoir
- have large middle (lumen) volume
- have less smooth muscles and fewer elastic fibers

Venules

small vessels that gather blood from the capillaries into the veins
- Venules radius is smaller than veins

Capillaries

Microscopic vessel through which exchanges take place between the blood and cells of the body (smallest);
- single layer of endothelial cell
- have a nucleus on the side
- single red blood cell wide; this is due to wanting efficient gas exchange
- Smallest radius of all of them

elastic recoil

the tendency for the lungs to recoil or reduce in volume after being stretched or expanded;
- we have recoil in the arteries because it needs lots of pressure to push the blood around the whole body efficiently
- It helps utilize the pressure gradient that the ventricle creates and extend it
- Elastic fibers have elastic recoil and they squeeze the blood down the blood vessels.