Transport (Chapter 9)

The Circulatory System Video

I. TRANSPORT: the absorption and circulation of materials within an organism

absorption- movement of materials across the cell membrane
circulation- movement of materials within a cell or between parts of an organism

A. Transport for PROTISTS (ex. amoeba, paramecium)

-no circulatory system is needed
-thin cell membrane: absorption occurs by diffusion & active transport

circulation occurs by CYCLOSIS (movement of cytoplasm)

[note] Circulatory Systems- are needed by "large" organisms

1. fluid (blood)
2. pump (heart)
3. vessels (arteries, veins, capillaries)

B. Transport for ANIMALS

1. HYDRA- no circulatory system is required, diffusion is the process in which materials are exchanged for a hydra

2.EARTHWORM- have a CLOSED CIRCULATORY SYSTEM (blood stays in vessels)

-blood flows in a circuit: aortic arches (5 hearts) pump blood
-red blood contains hemoglobin to carry oxygen
-exchange of materials takes place in capillaries

3. GRASSHOPPER- have an OPEN CIRCULATORY SYSTEM (blood flows into open spaces called sinuses)

-colorless blood does not contain hemoglobin; therefore, blood does not function in carrying oxygen
-have tubular heart that pumps blood into the dorsal artery towards the head into the sinuses, (HEMOCOEL is a network of sinuses)

4. HUMANS (Homo sapiens)- have a CLOSED CIRCULATORY SYSTEM

In 1628, William Harvey showed that the heart pumps blood to the organs through arteries and the veins carry blood back to the heart. Capillaries were not discovered until 1660.

The human CIRCULATORY SYSTEM consists of two sub-systems which are the Cardiovascular System & the Lymphatic System.

CARDIOVASCULAR SYSTEM

BLOOD VESSELS: (arranged in order blood flows within them)

1. Arteries- thick elastic walled

-blood under tremendous pressure moving away from the heart
-arterioles are small arteries that branch off and lead towards the capillaries

2. Capillaries- smallest vessels

-walls are one cell thick
-only allow one blood cell to pass through at a time for exchange of materials between blood & body, INTRACELLULAR FLUID (ICF): a fluid that helps move material between the capillaries & the body cells
-precapillary sphincters are rings of muscle that control the opening & closing of passage to the capillaries

3. Veins- thick walled less elastic than arteries

-blood not under pressure carrying blood toward heart
-veins have valves to prevent back flow of blood
venules are small veins that receive blood from the capillaries merge to form veins

HEART: made of cardiac muscle (striated, involuntary muscle) surrounded by pericardium (protective membrane)

4 chambers: 2 atria (receive blood) upper chambers of heart & 2 ventricles (pump blood out) lower chambers

Septum- separates left & right sides of the heart

because of the septum, the heart functions as a double pump: right side sends oxygen poor (deoxygenated) blood to the lungs; left side sends oxygen rich (oxygenated) blood to body

Valves- in the heart prevent back flow of blood cause "lub dup" sound which can be heard with a stethoscope

 

CIRCULATION OF BLOOD THROUGH THE BODY:

1. Pulmonary Circulation- this pathway in the body carries blood between the heart & lungs

2. Systemic Circulation- a pathway that carries blood between the heart & the rest of the body, excluding lungs

Types of Systemic Circulation

1. Coronary Circulation- Blood flows from the heart to the heart.
2. Hepatic Portal Circulation- Blood flows from the digestive tract to liver.
3. Renal Circulation- Blood flows to and from the kidneys.

click to see picture of cardiovascular system

THE HEARTBEAT CYCLE:

diastole- (relaxation) is period of relaxation, atria are filling with the blood

during diastole- the A-V valves are open, blood flows from the atria into the ventricles. 70% of ventricle is filled

systole- (contraction) is period of contraction, ventricle pump blood out

systole begins the contraction of the atria, this forces more blood into ventricle & then the ventricle contracts; the pressure of contraction closes the A-V valves & opens the semilunar valves

Sphygmomanometer- instrument used to measure the pressure of the blood in the artery of the upper arm

ex) 102/60

102 = systolic pressure

60 = diastolic pressure

 

THE CONTROL of the HEARTBEAT:

Sinoatrial Node (S-A node)- specialized cells in the atrium wall that initiates the heart to beat; also known as the pacemaker. S-A node is found in the wall of the right atrium.

Atrioventricular Node (A-V node)- triggers an impulse that causes the ventricles to contract

Electrocardiogram- (ECG or EKG) record electrical currents produced by the heart

Pulse-alternate expansion (high pressure) & relaxation (low pressure) which can be felt in arteries near surface of skin

LYMPHATIC SYSTEM

Lymphatic System is a system of vessels that returns excess fluid & proteins from the intercellular spaces to the blood.

Intercellular Fluid- is the fluid between cells & tissues, medium for exchange of materials.

Plasma is the fluid portion of the blood which carries dissolved nutrients within the blood and 'leaks' out of the capillaries into the intercellular space.

Lymph is the fluid inside vessels of lymphatic system. It is formed from the plasma that diffuses out of the capillaries and into the the lymphatic vessels.

Lymph Nodes (glands)- filter foreign matter from lymph, prevent cancer cells, bacteria, etc. from entering the blood

-also make white blood cells

Spleen is an organ near the stomach made of lymphoid tissue that filters out bacteria & worn out red blood cells.

 

1. CARDIOVASCULAR DISEASES- are malfunctions involving the heart and blood vessels.

a. High Blood Pressure- High blood pressure is the most common form of cardiovascular disease characterized by increased arterial pressure. This can be caused by a number of variables including stress, dietary factors, heredity, cigarette smoking, and aging.
High blood pressure can lead to damage to the lining of arteries and a weakening of the heart muscle.

b. Heart Attack- Myocardial-infarction (heart attacks), as they are
called, include:

1. Coronary Thrombus: Coronary Thrombus is a blockage in the coronary artery or its branches resulting in oxygen deprivation in the heart muscle. The deprived muscle usually becomes damaged.
2. Angina Pectoris: Angina Pectoris is a narrowing of the coronary arteries causing an inadequate supply of oxygen to the heart muscle. Often, an intense pain radiating from the chest to shoulder and arms is felt.

c. Heart Murmur- occurs when there is a hole in the septum or any of the heart valves are damaged.

2. BLOOD CONDITIONS- Blood conditions are abnormalities in the circulatory fluid.

a. Anemia: Anemia is the impaired ability of the blood to transport sufficient amounts of oxygen. This can be due to reduced amounts of hemoglobin and/or red blood cells.

b. Leukemia: Leukemia is a disease of the bone marrow characterized by uncontrolled production of nonfunctional white blood cells.

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