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Class Notes for Health Unit 4 Circulation and Respiration
The cardiovascular system consists of the heart, arteries veins and capillaries. It supplies the body with O2, nutrients and removes CO2 and waste products produced by the cells.
The Heart
The heart is a hollow, muscular four chambered pump. It is approximately the size of a fist and is divided into two sides.
Auricles/Atriums- upper chambers
Ventricles- lower chambers
The chambers are separated by valves which permit the blood to flow in one direction only from the auricle to the ventricle on the same side.
Tricuspid Valve- right side
Bicuspid Valve- left side
The human beat beats an average of 72 beats per minute at rest
Arteries- carry blood away from the heart. Carry highly oxygenated blood. Have thicker walls than veins and are set deeper in the body than veins. Arterial blood is bright red due to the high O2 content.
Veins- carry blood toward the body. Carry highly deoxygenated blood, have thinner walls than arteries and is a darker red color giving the name of “blue blood”.
Capillaries- minute vessels that connect arterioles (small arteries) and venules (small veins). Capillaries have a semi-permeable membrane which allows some substances like food and gas to pass through the cell membrane.
Blood- body fluid composed of approx. 78% water and 22% solids
Blood has several components
- Plasma- fluid part of blood
- Hemoglobin- iron protein which blood its red color
- Platelets- particles in blood that allow it to clot or coagulate and stop bleeding
Path of Circulation
The superior and inferior vena cava deposit deoxygenated blood into the right atrium. The blood passes through the tricuspid valve into the right ventricle.
The blood flows through the pulmonary artery to the lungs. Here it exchanges carbon dioxide for oxygen. The blood returns to the left atrium through the pulmonary vein.
The blood passes through the bicuspid valve into the left ventricle.
The blood now flows through the aorta (largest artery) to begin bringing food and O2 to every cell.
Blood Groups
All humans are in one of four blood types: A, B, AB or O.
The letters refer to a protein or antigen on the surface of red blood cells.
Each type is also grouped by its Rhesus factor or Rh factor. Blood is either Rh+ or Rh-. Rhesus refers to the Rhesus monkey in which the protein was first discovered.
In a transfusion, the donated blood must be accepted by the recipient’s blood or the red blood cells will clump together causing clots that can block a vessel and cause death.
Type O- is considered the “universal donor” because it can be donated to people of any blood type.
TypeAB+ is the “universal recipient” because these patients can receive any blood type.
“Rare Blood” refers to any type that requires more than 200 donors in order to find it.
Respiratory System
Respiration- the exchange of carbon dioxide for oxygen
When air is inhaled it enters the nasal cavity, travels to the larynx (voice box), through the trachea (windpipe) to the bronchial tubes and into each lung.
Bronchial tubes divide into smaller bronchioles and eventually into tiny air sacs called alveoli. The capillaries surrounding the alveoli exchange the CO2 for O2.
Respiration is accomplished via the contraction of the diaphragm (large flat muscle under the rib cage).
The size of the larynx (voice box) varies with individuals. During puberty the growth of the larynx is more rapid in males. This causes an increase in the length of the vocal folds.
Voice- is the result of air being driven out of the lungs which vibrates the vocal folds. The volume and force of the air determine the loudness or intensity of the voice.
Lungs- two cone shaped organs separated by the heart. The right lung is larger and broader than the left lung (the diaphragm is raised on the right side to accommodate the liver).
Costal breathing- upper ribs move first then the abdomen.
Diaphragmatic breathing- abdomen bulges out first then the rib cage raises. This is deeper breathing.
Disorders of the Circulatory and Respiratory Systems
Hypertension- is high blood pressure indicated by readings of greater than 130/90 when at rest. Influenced by heredity, diet, weight, lack of exercise and stress
Arteriosclerosis- is hardening of the arteries caused by the collection of plaque (fatty deposits of cholesterol)
Coronary Thrombosis- seizure of the heart muscle (myocardium) or better known as a heart attack. Also called a myocardial infarction (infarct is the death of tissue due to lack of O2)
Apoplexy- stroke caused by a hemorrhage (burst artery) in the brain.Loss of consciousness followed by paralysis are symptoms
Pneumonia- inflammation in the lungs causing fluid to accumulate in the lung tissue which affects breathing. Carries a 30% mortality rate if not treated
Asthma- an allergic reaction to any substance (allergen) causing a constriction in the bronchial tubes. Patient may use an MDI (metered dose inhaler) to dilate the breathing passages
Emphysema- alveoli burst leaving open spaces in the lung tissue (tissue does not regenerate). Associated with smoking, damp, cold weather or working in extremely dusty environments (construction or mining)