Principles of Biology By Frank H. Osborne, Ph. D. Lab 7 - Respiration and Circulation

Types of Respiration A. Cellular respiration 1. A cell of the body removes oxygen (O 2 ) from the blood which is part of the circulatory system. 2. The cell uses the O 2 to oxidize glucose to produce energy (ATP) and carbon dioxide (CO 2 ). 3. The CO 2 leaves the cell and enters the blood.

B. External respiration 1. Inspiration a. The diaphragm contracts and the chest wall expands to produce a partial vacuum in the lungs. b. Air enters the lungs because of the lower pressure. c. The air that enters the lungs has a high concentration of O 2 and a low concentration of CO 2 and H 2 O.

B. External respiration 2. Expiration a. The diaphragm relaxes and the chest wall contracts to produce a pressure in the lungs. b. Air leaves the lungs because of the higher pressure. c. The air that enters the lungs has a high concentration of CO 2 and H 2 O and a low concentration of O 2.

How a Human Breathes

Control of Respiration A. The diaphragm 1. The diaphragm is a muscle composed of smooth muscle cells. 2. The breathing cycle (one inhalation, one exhalation) occurs approximately 16 times per minute. 3. There is some voluntary control over the diaphragm.

Control of Respiration B. The nervous system 1. There is a CO 2 sensor located in the brain stem. 2. When the concentration of CO 2 increases, the autonomic nervous system causes the diaphragm to speed up.

Control of Respiration a. Holding the breath increases CO 2 concentration in the blood. i. After holding the breath, the breathing rate is faster. ii. Holding the breath deprives the heart and brain of oxygen and could cause permanent damage. Do not do it.

Control of Respiration b. Exercise increases the concentration of CO 2 in the blood. i. During exercise, the autonomic nervous system speeds up the breathing rate. ii. After exercise, the concentration of CO 2 lowers and the autonomic nervous system slows the breathing rate.

Control of Respiration

Circulation of the Blood A. The heart 1. The heart pumps the blood. 2. The right side of the heart collects the blood returning from the body and pumps it to the lungs. 3. The left side of the heart collects the blood returning from the lungs and pumps it to the body.

Heart: External

Heart: Section

Circulation of the Blood B. The arteries 1. The arteries carry blood away from the heart to the body or the lungs. 2. The contraction of the heart causes the arteries to contract using rings of smooth muscle. 3. The pulse is the contraction of the arteries.

B. The veins 1. The veins carry blood to the heart from the body or the lungs. 2. Veins do not have muscles. a. Blood is pushed in the veins by the motion of the body. b. Veins have valves to prevent the blood from flowing backward. c. Veins do not pulsate because they do not have smooth muscles that contract.

Gas exchange in the body

Types of Circulation 1. The pulmonary circulation a. The blood returns from the body to the right atrium of the heart. This blood is high in CO 2 and low in O 2. b. The right atrium pumps the blood into the right ventricle.

Types of Circulation c. The right ventricle pumps the blood to the lungs through the pulmonary arteries. d. The blood returns from the lungs through the pulmonary veins. This blood is high in O 2 and low in CO 2.

2. The systemic circulation a. The blood returns from the lungs to the left atrium of the heart. b. The left atrium pumps the blood to the left ventricle. c. The left ventricle pumps the blood to the body through the aorta. d. The blood returns from the body through the inferior and superior venae cavae.

Interrelationship Between Respiration and Circulation A. The respiratory system 1. Oxygen from the air enters the alveoli of the lungs. 2. The O 2 diffuses across the moist cell membranes into the capillaries of the circulatory system.

Interrelationship Between Respiration and Circulation 3. The CO 2 and some H 2 O in the blood diffuse from the circulatory system, across the moist cell membranes, into the alveoli. 4. The CO 2 and H 2 O leave the body and go into the air.

Interrelationship Between Respiration and Circulation B. The circulatory system 1. Blood high in O 2 leaves the lungs and goes to the heart. 2. The heart pumps the blood to the cells of the body.

Interrelationship Between Respiration and Circulation 3. The O 2 diffuses from the capillaries, across the moist cell membranes, into the cells of the body. 4. The CO 2 and H 2 O from cellular respiration diffuse from the cells of the body, across the moist cell membranes, into the capillaries.

Transport of Respiratory Gases 1. The circulatory system carries respiratory gases to and from the lungs. 2. The respiratory system exchanges respiratory gases with the air.

The End Lab 7 Respiration and Circulation