Chapter 10-11 - Circulatory and Blood & Immune Systems Flashcards
What is an artery? What is it made of?
A blood vessel that carries blood away from the heart. It has thick walls composed of distinct layers. The outer and inner layers are mostly composed of connective tissue. The middle layers are made up of muscle fibres and elastic connective tissue.
What causes blood to enter the artery? What happens to the artery?
A heart contraction makes blood surge from the heart into the arteries. Arteries stretch to accommodate inrush of blood.
What are arterioles? What are they composed of?
Smaller arteries. It has thick walls composed of distinct layers, the outer and inner layers are mostly connective tissue. The middle layer is composed of elastic fibres and smooth muscle.
What is a pulse? Where can you find your pulse?
Change in the diameter of the arteries following heart contractions. Your pulse can be felt near the wrist or on either side of your neck.
What is the autonomic nervous system?
The part of the nervous system that controls the motor nerves that regulate equilibrium and the diameter of the arterioles, and that is not under conscious control.
What is vasoconstriction and what causes it?
The narrowing of blood vessels, allowing less blood into the tissues. It’s caused by a nerve impulses which causes smooth muscles in the arterioles to contract.
What is vasodilation and what causes it?
The widening of blood vessels, allowing more blood into the tissues. It’s caused by the relaxation of the smooth muscles which causes a dilation of the arterioles.
What does vasodilation permit?
Permits the cells in the localized area to perform energy-consuming tasks.
What is atherosclerosis? What is formed?
A degeneration of blood vessels caused by the accumulation of fat deposits in the inner wall. Calcium and other minerals deposit on top of the lipid, forming plaque. (A form of arteriosclerosis)
What is arteriosclerosis?
A group of disorders that cause the blood vessels to thicken, harden, and lose their elasticity. They can narrow arteries and lead to high blood pressure.
What happens when plaque accumulates too much in the artery during atherosclerosis?
Blood clots form in the blood vessel when plaque gets too big and it bursts through the wall of the artery and it can block the artery and cut off blood flow.
What is an aneurysm? Why are they dangerous?
A bulge in the weakened wall of a blood vessel, usually an artery. They can lead to the rupture of blood vessels and causes a hemorrhage. (Escape of blood from a ruptured blood vessel)
What is the function of capillaries?
Sites of fluid and gas exchange between blood and body cells.
What are capillaries composed of?
A single layer of cells which is ideal for diffusion. They are between 0.4 and 1.0mm long with a diameter less than 0.005mm, which causes red blood cells to travel in a single file line.
What is the advantage and disadvantage of a capillaries structure?
Adv: Small distance for diffusion of gases and nutrients.
Dis: Capillary beds are easily damaged.
What determines whether a capillary is open?
Pre-capillary sphincter muscles regulate the movement of blood from the arterioles into capillaries.
What are the two methods to keep blood flowing one way back to the heart in veins? Explain them.
One way valves and skeletal muscles.
Valves: open in one direction, steering blood towards the heart. They restrict blood from flowing in the other direction.
Skeletal muscles: Venous blood pressure increases when skeletal muscles contract and push against the vein. Muscles bulge when they contract, thereby reducing the vein’s diameter. Pressure in veins increase and valves open.
How does pressure help flow blood towards the heart?
Nerve impulses causes smooth muscles in the walls of veins to contract, increasing fluid pressure during times of stress. Increased pressure drives more blood into the heart.
What are the roles of the veins?
Carries blood towards the heart in low-pressure canals, and act as blood reservoirs. (About 65% of blood volume can be found in veins.)
What are varicose veins and what causes them?
Disorder where the surface veins gradually become larger and begin to bulge. Caused by damaged valves and excessive blood pooling.
What is the pericardium?
The fluid-filled membrane that surrounds and bathes the heart, preventing friction between its outer wall and covering the membrane.
What is the septum?
A wall of muscle that separates the right and left sides of the heart.
What is the pulmonary circulatory system?
The system of blood vessels that carries deoxygenated blood to the lungs and oxygenated blood back to the heart.
What is the systemic circulatory system?
The system of blood vessels that carries oxygenated blood to the tissues of the body and deoxygenated blood back to the heart.
What is an atrium?
(plural: atria) A thin-walled chamber of the heart that receives blood from veins.
What is a ventricle?
A muscular, thick-walled chamber of the heart that delivers blood to the arteries.
From what system does the right atrium receive blood from?
The systemic system.
From what system does the left atrium receive blood from?
The pulmonary system.
What is the atrioventricular valve (AV)? What is it composed of?
A heart valve that prevents the back flow of blood from a ventricle into an atrium. AV separates the atria from the ventricles. It is supported by bands of connective tissue called chordae tendine.
What is the semilunar valve? What shape are they?
A valve that prevents the back flow of blood from an artery into a ventricle. Semilunar valves separate ventricles from arteries. Valves are half-moon shaped (semilunar).
What is the superior vena cava?
Vein that carries deoxygenated blood from the head and upper body to the right atrium.
What is the inferior vena cava?
Vein that carries deoxygenated blood from all veins below the diaphragm to the right atrium.
What is the aorta?
The largest artery in the body that crries oxygenated blood to the tissues.
What is the coronary artery?
An artery that supplies the cardiac muscle with oxygen and nutrients. It branches form the aorta.
What is angina?
Chest pain that occurs when too little oxygen reaches the heart.
What is the SA node? What are its functions?
The sinoatrial node is a small mass of tissue in the right atrium that originates the impulses stimulating the heartbeat. It sets the heart’s tempo or beat rate. It also acts as a pacemaker, setting the rhythm of about 70 beats/min.
What is the AV node? What are its functions?
The atrioventricular node is a small mass of tissue in the right atrioventricular region through which impulses from the sinoatrial node are passed to the ventricles. It serves as a conductor, passing nerve impulses via two large nerve fibers (Purkinje) through the septum to the ventricles.
What are Purkinje fibers?
A nerve fiber that branches and carries electrical impulses throughout the ventricles.
What is the sympathetic nervous system? What are its functions?
A division of the autonomic nervous system that prepares the body for stress. The system increases heart rate which increases blood flow to tissues, enabling the body to meet increased energy demands.
What is the parasympathetic nervous system?
A division of the autonomic nervous system that returns the body to normal resting levels following adjustment to stress.
What is tachycardia? How does it occur?
When heart rate exceeds 100 beats/min. This can result from exercise or drugs such as caffeine or nicotine.
What is the myogenic muscle?
A muscle that contracts without external nerve stimulation. (Automatic: Ex. cardiac muscle)
What is cardiac catheterization? What instrument does it need? Where does it go?
A method of detecting coronary artery blockage. A catheter is used, which is a small, thin hollow tube. It is passed into an artery in the groin.
What can be taken with the catheter and what does it determine?
Blood samples can be taken with the catheter to determine how oxygen is in the blood in different chambers.
What are the lubb-dubb sounds caused by?
The closing of heart valves.
What is diastole? What happens to the atria during diastole?
Relaxation (dilation) of the heart. The atria and ventricles are relaxed and when the atria are relaxed, they fill with blood.
What is systole? What happens to the atria during systole?
Contraction of the heart, during which blood is pushed out of the heart. The atria contracts, increasing fluid pressure and forcing the AV valves open.
What creates the lubb sound?
Blood flows from the atria to the ventricles. Ventricles contract and the pressure forces the AV valves shut which produces a heavy lubb sound.
What creates the dubb sound?
Closing of the semilunar valves create a dubb sound.
What causes heart murmurs?
Occurs when valves don’t close completely. Blood leaks past the closed heart valve because of an improper seal.
What is foxglove and what is it used for?
Foxglove is a garden plant. An ingredient called digitalis initiates strong, regular heart contractions and is used to treat congestive heart failure.
What is nitroglycerin and what is it used for?
Nitroglycerin is an explosive used to prevent heart attacks as it relaxes smooth muscle and dilates blood vessels.
What are beta-blockers and what are they used for?
Beta-blockers are drugs important for people with irregular heartbeats or who display the effects of high blood pressure.
What is epinephrine and how do beta-blockers affect it?
Epinephrine is a stress hormone. It attaches to receptors on the heart and blood vessels, increasing heart rate and narrowing blood vessels. Both effects can increase blood pressure. Beta-blockers tie up receptor sites that accept epinephrine.
What are the two types of beta-receptors?
Beta 1 and Beta 2. Beta 1 is found on the surface of the cardiac muscle and affects the speed and strength of heart contractions and directly influences blood pressure. Beta 2 is found primarily in the blood vessels and the bronchioles leading into the lungs.
What is arrhythmia and what causes it?
An irregular heartbeat caused by a blocked coronary artery.
What is ventricular fibrillation? How does the heart respond to it?
When cells within the ventricle responds to toxins and begins to contract wildly. As the heart fibrillates, blood is not pumped in a coordinated fashion and the heart responds by beating faster.
What is cardiac output? What factors affect cardiac output?
The amount of blood pumped from the heart each minute. Stroke volume and heart rate affect cardiac output.