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34 Cards in this Set

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Function of Animal circulatory systems
1. Transport of materials
Gases
Nutrients
Wastes
Hormones
2. Contain cells to fight infection
3. Helps stabilize the pH and ionic concentration of the body fluids
4. Helps maintain body temperature by transporting heat
No circulatory system
small animals may not need a circulatory system because the interior cells are close to the surface
Oxygen absorbed from the environment by surface cells can diffuse to interior cells
Wastes produced by interior cells move a short distance to the surface and diffuse into the environment
Open circulatory system
Blood is pumped from the heart through blood vessels
Blood then leaves the blood vessels and enters body cavities, where the organs are bathed in blood
Closed circulatory system
Blood is confined to vessels
Valves prevent backflow within vessels
Blood usually contains cells and plasma (liquid)
Heart
Heart is two separate pumps separated by a septum
Left side of Heart
pumps blood to body (systemic)
Right side of heart
pumps blood to lungs (pulmonary)
Two chambers of heart
Ventricle
Atria
Ventricles
pump blood to the body (left ventricle) or to the lungs (right ventricle)
Atria
receive blood when relaxed and fill ventricles when they contract
Cardiac Cycle
one complete sequence of pumping and filling of the heart
Systole – contraction phase
Diastole – relaxation phase
Atrioventricular (AV) valves
located between atria and ventricles prevents backflow into atria
Semilunar valves
located at exits from heart and prevent backflow into ventricles
Sinoatrial (SA) node
nervous tissue that serves as cardiac pacemaker
Stimulation from this node causes both the atria to contract simultaneously (not the ventricles)
Atrioventricular (AV) node
slower action than SA node
Stimulation causes ventricles to contract
Slower action means that ventricles always contract after atria
Arteries –
carry blood away from the heart

Very thick and elastic walls allow arteries to absorb pressure from pumping
Arteries maintain blood pressure
Outer layer of circular muscle controls diameter of an artery, thus controlling blood flow
Arterioles lead into
Capillaries
Capillaries
are the smallest blood vessels – diameter is so small that red blood cells travel single-file

Capillaries are specialized for exchange of substances with the interstitial fluid - fluid that surrounds and bathes cells

Blood cells and large proteins remain in the capillaries although fluid can leave and return
Venules lead into
Veins
Veins
carry blood back to the heart
Veins have greater capacity than capillaries or arteries, and so have low pressure – helps prevent backflow
Contraction of skeletal muscle squeezes veins and helps carry blood back to the heart – also helps regulate blood flow
Two parts of Blood
1. Liquid (plasma)
2. Cells
Liquid (plasma)
Contains dissolved gasses, nutrients, wastes, salts, and proteins

Plasma proteins also assist in transporting large organic molecules
Red blood cells (erythrocytes)
contain hemoglobin, a protein which binds oxygen
Continuously produced in the red marrow of the skull, ribs, vertebrae, and ends of the long bones
White blood cells (leukocytes)
required for immune response
Platelets
required for clotting
Platelets adhere to exposed collagen in damaged blood vessels and release clotting factors
Clotting factors catalyze conversion of fibrin – sticky threads that “seal” the wound
Respiratory system
primary function is to obtain oxygen for use by body's cells & eliminate carbon dioxide that cells produce
Pathway of air
nasal cavities (or oral cavity)
pharynx
trachea
primary bronchi (right & left)
secondary bronchi
tertiary bronchi
bronchioles
alveoli (site of gas exchange)
Alveoli
tiny air sacs at the very tips of bronchioles
Breathing
active process that requires contractions of a sheet of skeletal muscle known as the diaphragm
Keeps oxygen concentration in blood lower than oxygen concentration in alveoli
Keeps carbon dioxide concentration in blood higher than carbon dioxide concentration in alveoli
Partial pressure
another way of saying “concentration”
Gas exchange
occurs between alveoli and capillaries via simple diffusion
Hemoglobin saturation
Because almost all oxygen in the blood is transported by hemoglobin, the relationship between the concentration (partial pressure) of oxygen and hemoglobin saturation (the % of hemoglobin molecules carrying oxygen) is an important one
Oxygen binding to hemoglobin is
cooperative
stages of Carbon Dioxide Transport
Body tissues produce carbon dioxide
Carbon dioxide diffuses into interstitial fluid and plasma
Some carbon dioxide is picked up by hemoglobin
Most carbon dioxide reacts with water to eventually form bicarbonate ion – transported to lungs by bloodstream
Bicarbonate ion converted back into carbon dioxide and water at the lungs
Carbon dioxide passively diffuses into alveolar space and is expelled during exhalation