circulatory system Flashcards
functions of circulatory system
- transports gases, nutrient molecules, hormones and waste materials
- regulates internal temperature and transports hormones (homeostasis)
- protects against blood loss from injury and against disease
major components of circulatory system
heart, blood vessels, and blood
three main types of blood vessels
arteries, veins, and capillaries
arteries
carry blood away from the heart (usually oxygen rich), relaxes and contracts as blood surges from the heart
capillaries
tiny vessels where gases, nutrients, and wastes are exchanged as capillaries are permeable
veins
carry blood to the heart (usually oxygen poor)
structure of an artery
have thick, muscular, elastic walls that maintain blood pressure between pump cycles
externa
tough, outer connective tissue
media
thick layer of smooth muscle and elastin fibers
intima
smooth endothelium forming the lining of the lumen
aneurysm
inner wall of artery bulges outward putting pressure on outer wall (genetic)
arterioles
small arteries that relax and contract when flow changes
aneurysm
inner wall of artery bulges outward putting pressure on outer wall (genetic)
vasoconstriction
nervous system causes arterioles to contract in times of emergency which increases blood pressure to certain parts of the blood while restricting it to others
vasodilation
nervous system causes arterioles to relax (blushing)
atherosclerosis
fat droplets block flow of blood and can lead to heart disease
treatment of atherosclerosis
bypass surgery or angioplasty
veins
thinner walls with a larger inner circumference, not muscular or elastic, cannot contract like arteries but can dilate to become very wide
veins have one way valves
needed to prevent blood from flowing backwards (no pressure)
blood is moved through veins by
contraction and relaxation of skeletal muscles around vein
stretching
increases blood flow which has a massaging effect
vericose veins
pooling and back pressure of blood causes damage to surrounding tissues. valves misfunction and venules burst because of age obesity, poor nutrition and posture
capillaries are tiny
only one cell thick and wide enough for a single blood cell to fit it through
bruise
capillaries get damaged and blood/plasma rushes into interstitial spaces
capillaries nutrients
oxygen, monosaccharides, amino acids, fatty acids, and hormones
functions of the heart
- pumps blood to lungs (pulmonary circulation) and to body (systemic circulation)
- keeping oxygen rich and oxygen poor blood separated
- ensuring blood only flows in one direction
waste products
CO2, Urea, Ammonia
the heart walls
made of cardiac muscle
the heart has valves so
blood only flows one way
contractions of heart
rhythmic and involuntary
the heart has four chambers
2 atria (top) - collectors that are filled with blood returning to heart 2 ventricles (bottom) - pumps that send blood back out of heart
the heart needs
its own supply of O2 and nutrients
the coronary artery
supplies the heart with O2 and nutrients. This small artery, if blocked by fats, leads to heart disease
atria
chambers that fill with blood returning to the heart either from the lungs (left) or from the body (right)
ventricles
chambers that receive blood from the atria and pump it either to the lungs (right ventricle) or the body (left ventricle)
septum
muscular wall that separates the left and right sides of the heart
superior vena cava
collects deoxygenated blood from the head, chest, and arms
inferior vena cava
collects deoxygenated blood from central and lower body
vena cava
combine and dump blood into the right atrium
pulmonary arteries
the blood vessels that carry the blood form the right ventricles to the lungs
pulmonary veins
blood vessels that carry blood back from the lungs to the left atrium
aorta
the largest blood vessels in the body that leaves the left ventricle carrying oxygenated blood to the body
tricuspid valve
the atrioventricular valve that has three flaps and separates the right atrium from the right ventricle
bicuspid valve
the atrioventricular valve that has two flaps and separates the left atrium from the left ventricle
semilunar valves
half-mooned in shape, these valves are found both in the pulmonary trunk and the aorta
