Circulatory System Review

These flashcards cover the key concepts related to the circulatory system, including its functions, structure, and related processes.

What are the transportation functions of blood?

Transport of oxygen and nutrients to body cells, carbon dioxide and wastes from body cells, and hormones to various cells.

What are the maintenance functions of blood?

Maintains constant pH level of body fluids, water content and ion concentration, and body temperature by distributing heat.

What are the protective functions of blood?

Protects against disease-causing microorganisms and prevents blood loss through clotting.

What are the two main components of blood and their percentages?

Plasma (55%) and formed elements (45%).

What are the three types of formed elements in blood?

Erythrocytes (red blood cells), Leucocytes (white blood cells), and Platelets.

What is plasma composed of?

Mixture of water (91%) with dissolved substances such as nutrients, ions, hormones, gases, and wastes.

What is the function of plasma?

Transport components of blood throughout the body.

What is the shape of red blood cells and why is this significant?

Biconcave shape, increasing surface area for oxygen exchange.

Why do red blood cells lack a nucleus?

To increase flexibility for moving through blood vessels and to create more room for hemoglobin.

What is the main function of red blood cells?

To transport oxygen from the lungs to cells throughout the body.

What percentage of oxygen is transported by erythrocytes and in what form?

97% as oxyhemoglobin; 3% is carried in solution in plasma.

What percentage of blood is made up of white blood cells?

Only 1% of blood.

What are the functions of white blood cells?

Fighting infection, producing antibodies, and forming memory cells.

What are two important types of white blood cells?

Lymphocytes and Macrophages.

What is the structure of platelets?

Small fragments of cells.

What is the function of platelets?

Blood clotting.

How does hemoglobin enhance oxygen transport?

It combines with oxygen to form oxyhemoglobin, increasing the blood's oxygen-carrying capacity.

Describe the oxygen-hemoglobin dissociation cycle.

In lungs, high O₂ concentration causes O₂ to bind with hemoglobin. In tissues, low O₂ concentration causes oxyhemoglobin to dissociate, releasing O₂ to cells.

What are the three ways carbon dioxide is transported in blood?

Dissolved in plasma (7-8%), as carbaminohemoglobin (22%), and as bicarbonate ions (70%).

What happens to red blood cells in a hypertonic solution?

Water moves out of the cell (crenation) due to higher solute concentration outside the cell.

What happens to red blood cells in an isotonic solution?

Water and salt levels inside and outside remain equal.

What happens to red blood cells in a hypotonic solution?

Water moves into the cells (hemolysis) due to higher solute concentration in the RBC.

What are the three main types of blood vessels?

Arteries, capillaries, and veins.

What is the function of arteries?

To take blood away from the heart.

Describe the structure of arteries.

Thick, smooth, elastic walls; small lumen diameter; can undergo vasodilation and vasoconstriction.

What is the function of capillaries?

To carry blood between cells for material exchange.

Describe the structure of capillaries.

Microscopic, one cell layer thick allowing easy material exchange.

What is the function of veins?

To take blood towards the heart.

Describe the structure of veins.

Little smooth muscle; large lumen diameter; contain valves to prevent backflow.

Where is the heart located?

Between the two lungs.

What is the pericardium?

The membrane that encloses the heart.

What tissue makes up the wall of the heart?

Cardiac muscle.

What are the four major blood vessels of the heart?

Superior and inferior vena cava, pulmonary arteries, and aorta.

What is the function of the right atrium?

Receives deoxygenated blood from the body.

What is the function of the right ventricle?

Pumps deoxygenated blood to the lungs.

What is the function of the left atrium?

Receives oxygenated blood from lungs.

What is the function of the left ventricle?

Pumps oxygenated blood to the body.

What are heart valves and their function?

Prevent blood from flowing backwards.

What are the chordae tendineae?

Fibrous connective tissue that holds the heart together.

What is the septum?

Heart muscle that separates the left and right sides.

What are the two main phases of the cardiac cycle?

Systole (pumping phase) and diastole (filling phase).

Describe the three phases of the cardiac cycle.

1) Diastole: atria fill with blood. 2) Atrial systole: atria contract. 3) Ventricular systole: ventricles contract.

What is cardiac output?

Volume of blood leaving one ventricle every minute.

What are blood transfusions and when are they needed?

Transfer of blood from donor to patient; needed for excessive blood loss or diseases.

What is an antigen?

Substance capable of inducing an immune response.

What are the two main antigens in the ABO blood group system?

Antigen A and Antigen B.

What blood type is considered the 'universal donor' and why?

Type O, it has no A or B antigens.

What blood type is considered the 'universal receiver' and why?

Type AB, it has no anti-A or anti-B antibodies.

What determines whether a person is Rh positive or Rh negative?

The presence or absence of Rh antigens on red blood cells.

What is the purpose of blood clotting?

To minimize blood loss and prevent infection.

What is vasoconstriction in blood clotting?

Muscles in small arteries constrict to reduce blood flow.

What is a platelet plug?

A cluster of platelets that reduces blood loss at the site of a vessel injury.

What is fibrin and its role in blood clotting?

Protein that forms a mesh to hold the platelet plug in place.

What is lymph?

Fluid returned to the circulatory system by the lymphatic system.

How does lymph differ from blood in terms of circulation?

Lymph is a one-way system flowing away from tissues.

What are lymph capillaries?

Closed tubes between cells allowing proteins and microorganisms to pass through.

What are lymph nodes and where are they found?

Bean-shaped structures containing lymphoid tissue found in various regions of the body.

How does the lymphatic system help defend against disease?

Lymph nodes destroy pathogens by phagocytosis.

What is phagocytosis?

When a cell consumes a membrane-wrapped vesicle.

What is the cytoplasm?

Jelly-like substance suspending organelles.

Is hemoglobin a carbohydrate, lipid, or protein?

Protein.

What color is oxyhemoglobin?

Bright red.

Name two membrane-bound organelles.

Golgi apparatus and mitochondria.

Why can't red blood cells undergo cell division?

They lack a nucleus and organelles.

Why can't sodium and potassium ions be actively transported across red blood cell membranes?

No mitochondria means no ATP can be produced.

By what process does oxygen enter a red blood cell?

Diffusion.