Human Circulatory System Functions

The human circulatory system is responsible for ______, transport, homeostasis and protection.

Blood is made of cells suspended in ______.

______ are cell fragments, also known as thrombocytes, that play a pivotal role in homeostasis and blood clotting when there's an injury.

The heart is composed of three layers: the endocardium, myocardium, and ______, also known as the visceral pericardium.

The two atrioventricular valves, which control blood flow between the atria and ventricles, are the tricuspid and ______ valves.

The semilunar valves in the heart are the pulmonary and ______ valves, which prevent backflow of blood into the ventricles.

In the pulmonary circuit, blood flows from the right ventricle to the pulmonary artery, then through pulmonary arterioles, ______, and venules, before returning to the left atrium.

In the systemic circuit, blood flows from the left ventricle through the aorta, upper and lower body arteries and veins, and eventually returns to the ______ atrium.

The cardiac cycle involves two main phases, ______ and diastole, which represent the contraction and relaxation of the heart muscle, respectively.

______ can be measured using a sphygmomanometer, which reflects the force that blood exerts on the walls of blood vessels.

The higher reading of blood pressure, known as ______, indicates the pressure in the arteries when the ventricles contract.

The lower reading of blood pressure, known as diastole, reflects the pressure in the arteries when the ventricles ______.

Blood pressure in arteries is generally higher than in veins or capillaries; blood ______ follows a pattern influenced by distance from the heart.

The ______ is involved in detecting blood pressure and relaying information to the brainstem for blood pressure regulation.

The medulla oblongata, via the autonomic nervous system, adjusts heart rate and ______ diameter to maintain homeostasis.

The arterioles contribute to blood pressure regulation through vasoconstriction and ______, which narrow and widen blood vessels, respectively.

The primary function of the circulatory system is to ______ the flow of blood throughout the body.

The objective is to explain the cardiac cycle and its relationship to ______.

The important thing is to discuss how different ______ systems work together to regulate the factors that influence blood pressure.

______ blood cells, or erythrocytes, do not have a nucleus, mitochondria, and other organelles.

RBCs are biconcave in ______ for easier movement in narrow blood vessels.

The lifespan of red blood cells is approximately 120 days, after which they need to be replaced ______.

Mature red blood cells are the only cells that express ______, a protein that binds oxygen.

______ blood cells, or leukocytes, are important for fighting viruses and making antibodies.

Veins have the largest ______ compared to arteries and capillaries because blood pressure in veins is so low.

If the pressure in veins is so low, skeletal muscle contraction propels blood through open ______ toward the heart, against the force of gravity.

Capillary walls are only one cell layer ______ to facilitate the diffusion of water and dissolved substances between the capillary and the interstitial fluid.

Arterioles regulates the flow of blood ______ the capillaries and venules are the smallest veins and receive blood from capillaries.

There are a number of differences of arteries and veins according to direction of blood ______.

There are a number of differences of arteries and veins according to the ______ of blood.

There are a number of differences of arteries and veins according to muscle layer thickness and ______ diameter.

There are a number of differences of arteries and veins according to the presence of ______.

Ventricle ______ occurs when the semilunar valve shuts, preventing flow back into the ventricle.

The circulatory system provides ______ by destroying foreign particles and facilitating blood clotting.

Arterioles also play a role in the ______ of oxygen and nutrients for water products.

The cardiac cycle consists of the events that occur with each ______ and relaxation of the heart muscle.

The arterial walls are thinner than the walls of the ______.

During ventricular contraction, the ______ valves open, allowing blood to flow out of the heart into the arteries.

Elastic recoil of ______ sends blood forward into rest of circulatory system.

The aorta and ______ expand and store pressure in elastic walls to help with continuous blood flow.