Circulation and Gas Exchange

Flashcards about Circulation and Gas Exchange.

Circulatory Systems

Systems that link exchange surfaces with cells throughout the body, important for larger animals.

Gastrovascular Cavities

Simple animals with a body wall only 2 cell-layers thick, where the cavity functions in both digestion and circulation.

Open Circulatory System

A circulatory system where blood empties into the hemocoel, bathing the organs.

Hemocoel

The open space within the body in an open circulatory system where blood bathes the organs.

Closed Circulatory System

A circulatory system where blood is confined in vessels.

Atrium (Atria)

Chambers of the heart that receive blood from the body.

Ventricle

Chambers of the heart that send blood out into the body.

Pulmonary Circulation

The circulation responsible for pumping blood to and receiving blood back from the lungs.

Systemic Circulation

Circulation responsible for pumping blood to and receiving blood back from the body.

Cardiac Cycle

Alternating contraction and relaxation of the heart chambers.

Systole

The pressure during the contraction of the ventricles.

Diastole

The pressure during the relaxation of the ventricles.

Atrioventricular Valves (AV Valves)

Valves that separate each atria from the ventricle below it.

Tricuspid Valve

Separates the right ventricle and atrium.

Bicuspid Valve

Separates the left ventricle and atrium.

Semilunar Valves

Valves that keep blood that has just been pumped out of the heart from flowing backwards into the heart.

Pacemaker

Area of muscle that sets the pace for other muscle cells; required for coordinated contraction.

Sinoatrial Node (SA Node)

Heart's primary pacemaker, a small mass of muscle cells in the wall of the right atrium.

Atrioventricular Node (AV Node)

A second mass of cells that signals ventricular contraction after a delay.

Arteries and Arterioles

Carry blood away from the heart; have thick, muscular, elastic walls.

Venules and Veins

Provide low-pressure pathways for blood back to the heart; have thinner walls and one-way valves.

Sphincter Muscles

Rings of muscle around a tube that regulates flow via contraction.

Capillaries

Where the exchange of wastes, nutrients, gases, and hormones between blood and body cells occurs; walls are only one cell thick.

Erythrocytes (RBCs)

Red blood cells; primary job is to transport oxygen from lungs to cells of the body.

Hemoglobin (Hb)

Red pigment molecule in RBCs that carries oxygen.

Leukocytes (WBCs)

White blood cells; main function is to fight infections.

Platelets

Fragments that break off large megakaryocytes cells and are involved in blood clotting.

Coagulation Cascade

Complex series of chemical events that result in the activation of the enzyme thrombin.

Multipotent Stem Cells

Multipotent stem cells in the red bone marrow that produce all types of blood cells.

Cellular Respiration

The process where organisms use up O2 and generate CO2 as a waste product.

Respiratory System

The increase of surface area that keeps moisture in order to facilitate gas exchange.

Bulk Flow

Process in both respiratory and circulatory systems using movements of fluids or gases.

Diffusion

Process present in both respiratory and circulatory systems involving movement of molecules from high to low concentration.

Ventilation

Increasing flow of medium over respiratory surface (individual gill filaments).

Countercurrent Exchange

Opposite flow of adjacent fluids that maximizes transfer rates.

Book Lungs

Based on folds of tissue and found in arachnids (spiders).

Tracheae

Based on branching pipes where they have openings all over the body and is the respiratory system in insects.

Lungs

Delicate, moist, respiratory chambers deep within the body in land snails and vertebrates.

Conducting Portion

All the passageways that carry air to and from the lungs.

Gas Exchange Portion

Sacs called alveoli which is where gas exchange occurs.

Pharynx

Chamber where the paths from the mouth and nose meet.

Larynx

First part of the pathway that is exclusively for gas flow (no food flow); also houses the vocal cords.

Trachea

Rigid tube leading to the lungs; designed with cartilage rings for support and flexibility.

Alveoli

Clusters of alveoli surrounded by capillary beds where gas exchange occurs.

Inhalation

Air is actively inhaled; is a very active process requiring muscular contraction.

Exhalation

Air is passively exhaled; is a very passive process requiring muscle relaxation to occur.