Test 3 (Chapters 8-10) Flashcards
What is the function of arteries?
- Carry blood away from the heart
- transport blood under high pressure
What is the function of capillaries?
exchange solutes and water with cells of the body
What are the functions of veins?
return blood to the heart
What is the structure of arteries?
thick walled and three layers
- innermost: endothelium
- middle: smooth muscle
- outer: connective tissue
What is the path of blood flow?
Heart to arteries to arterioles and then to capillaries
What are arterioles?
smallest arteries
What is the function of precapillary sphincters?
control of blood flow into capillaries
What is vasodilation?
increases the blood flow into capillaries
What is vasoconstriction?
decreases blood flow to capillaries
What is the structure of capillaries?
- smallest blood vessels
- thin walled: one cell layer thick
- porous
What are capillary beds?
extensive networks of capillaries
What is the function of capillary beds?
selective exchange of substances with the interstitial fluid
What is the structure of veins?
- three layers, thin walled
- larger lumen than arteries
- high distensibiltiy
What are the functions of veins
- carry blood toward heart
- blood flow (capillaries-venules-veins-heart)
- serve as blood volume reservoir
What are the mechanisms of blood return?
- contraction of skeletal muscles
- one-way valves
- pressure change associated with breathing
What is the function of the lymphatic system?
- maintains blood volume
- also functions as immune system
What is the structure of the lymphatic system?
- blind-ended capillaries
- lymphatic vessels
- lymph derived from interstitial fluid
What is the heart surrounded by?
A fibrous sac called the pericardium
What is the epicardium?
thin layer of epithelial and connective tissue
What is the myocardium?
Thick layer of cardiac muscle
What is the endocardium?
thin layer of endothelial tissue
What are the four chambers of the heart?
- two atria
- two ventricles
What is the function of valves?
prevent backflow
How many valves are in the heart?
- 2 atrioventricular valves (tricuspid and bicuspid)
- 2 semilunar valves (pulmonary and aortic)
How is blood oxygenated?
- Blood goes to right atrium
- Then to through the right atrioventricular valve to the right ventricle
- Then through the pulmonary semilunar valve to the pulmonary trunk and lungs
- Blood is oxygenated in pulmonary capillaries
- oxygenated blood travels through pulmonary valve to the left atrium
- Then through the left atrioventricular valve to the left ventricle
How is oxygenated blood delivered to the tissues?
- From left ventricle through the aortic semilunar valve to the aorta
- Through branching arteries and arterioles to tissues
- Through arterioles to capillaries
- Then to venules and veins
- Then to the vena cava and right atrium
What occurs during atrial systole?
- both atria contract
- AV valves open and semilunar valve shut
- ventricles fill
What happens during ventricular systole?
- Both ventricles contract
- AV valves close, semilunar valves open
What happens during diastole?
- Atria and ventricles relax
- semilunar valves close
What happens during the lub sound of a heart beat?
closing of both AV valves during ventricular systole
What happens during the dub sound of a heart beat?
closing of both semilunar valves during ventricular diastole
What are the causes of heart murmurs?
blood flow is disturbed (may be sign of a valve problem)
What is the function of the SA node?
- cardiac pacemaker
- initiates heart beat
- pace can be modified by nervous system
What is the function of the AV node?
relays impulse
What is the function of AV bundles and Purkinje Fibers?
carry impulse to ventricles
What is the function of an EKG?
Tracks electrical activity of the heart
What is a P wave?
impulse across atria
What is the QRS complex?
spread of impulse down the septum, around ventricles and Purkinje Fibers
What is the T wave?
end of electrical activity in the brain
What can EKGs detect?
- arrhythmias
- ventricular fibrillation
What is blood pressure?
the force that blood exerts on the wall of vessels
What is systolic pressure?
highest pressure as blood is ejected during ventricular systole
What is diastolic pressure?
lowest pressure during ventricular diastole
How is blood pressure measured?
By a sphygmomanometer
systolic <80 mmHg
What is hypertension (silent killer)?
High blood pressure
What is hypotension?
Low blood pressure
What are the signs of hypotension?
- dizziness
- fainting
What are the causes of hypotension?
- orthostatic
- severe burns
- blood loss
What are baroreceptors?
pressure receptors in the aorta and carotid arteries
How is blood pressure regulated?
- Blood pressure rises, vessels stretched
- Signals are sent to the cardiovascular center in the brain
- heart is signaled to lower heart rate and force contraction
- arterioles vasodilate, increasing blood flow to tissues
- combined effect lowers blood pressure
What is the function of sympathetic nerves?
constrict blood vessels, raising blood pressure
What is the function of the parasympathetic nerves?
dilate blood vessels, decreasing blood pressure
What hormone regulates blood pressure?
epinephrine
What dictates local blood flow?
local requirements
What is the function of exercise on blood pressure?
increased blood flow and cardiac output
What is angina pectoris?
narrowed coronary arteries impair blood flow (no damage)
What is a myocardial infarction (heart attack)?
permanent cardiac damage due to blockage in a coronary artery
What is congestive heart failure?
decrease in pumping efficiency