Cardiovascular and Respiratory System Concepts

These flashcards cover key vocabulary and concepts related to the cardiovascular and respiratory systems, focusing on definitions and important physiological mechanisms.

Vasoconstriction

The contraction of smooth muscle in blood vessel walls, leading to a smaller opening.

Vasodilation

The relaxation of smooth muscle in blood vessel walls, leading to a larger opening.

Hydrostatic Pressure

The pressure exerted by a fluid at equilibrium due to the force of gravity.

Resistance

The opposition to blood flow within the circulatory system.

Hematocrit

The percentage of blood volume occupied by red blood cells.

Alveoli

The small air sacs in the lungs where gas exchange occurs.

Ventilation

The process of breathing in and out; the movement of air into and out of the lungs.

Respiration

The gas exchange that occurs in the capillaries.

Countercurrent Exchange

A mechanism in which fluids move in opposite directions to maximize gas exchange.

Nernst Equation

An equation used to calculate the equilibrium potential for an ion across a membrane.

Chemoreceptors

Sensory receptors that detect changes in the chemical composition of the blood, particularly pH and gas levels.

Equilibrium Potential

The membrane potential at which the concentration gradient and electrical gradient for a specific ion are balanced.

Skeletal Muscle Pump

The mechanism by which skeletal muscles help facilitate venous return by contracting and squeezing veins.

Edema

Swelling caused by excess fluid trapped in the body's tissues.

Spirometry

A test used to measure lung volumes and capacities during breathing.

What is PO2 when total atmospheric pressure is 800 mmHg?

A. 168 mmHg (correct) (21%)

What happens to oxygen when it moves into the pulmonary capillaries?

C. Into, external respiration (correct)

How is most oxygen carried in the bloodstream?

C. Bound to hemoglobin (correct)

How is most carbon dioxide carried in the bloodstream?

D. As bicarbonate (HCO3-) (correct)

What is the pH condition when there are high levels of H+?

C. Low pH; acidic (correct)

At high PO2 levels, how is oxygen related to hemoglobin?

B. Bound; unbound (correct)

What happens if PO2 in the tissues decreases surrounding a capillary bed?

D. Oxygen binding affinity to hemoglobin would decrease, so more oxygen would be released (correct)

How does the respiratory system remove CO2 from the body?

B. Bicarbonate (HCO3-) is converted to CO2 at the lungs (correct)

What are respiratory media?

B. Water or air (correct) and C. An animal’s source of oxygen (correct)

If volume in the lungs increases, what happens to pressure in the lungs?

B. Increases, decreases (correct)

What describes a cocurrent exchange mechanism?

A. Fluids move the same direction (correct) and C. A maximum of 50% gas exchange can occur (correct)

What describes a countercurrent exchange mechanism?

B. Fluids move opposite directions (correct) and D. More than 50% gas exchange is possible (correct)

Where does countercurrent exchange mechanism occur?

C. It occurs in the gill system of fishes (correct)

What would increase oxygen carrying capacity?

A. Increasing hematocrit (correct) and C. Increasing the amount of respiratory pigment (correct)