Chapter 15 - Cardiovascular system Flashcards
How much blood is pumped through the body each day?
7000 liters
How many times does the heart contract in an average lifetime?
2.5 billion times
What makes up the cardiovascular system?
heart and blood vessels
Name the 2 circuits of the blood vessels:
- pulmonary circuit
- systemic circuit
Describe the heart:
hollow, cone-shaped, muscular pump
Name the 4 chambers of the heart:
2 atria , 2 ventricles
What do the atria do?
blood storage
What do the ventricles do?
pump blood
Does the heart change with body size?
varies with body size
What cavity does the heart lie in?
thoracic cavity
Where does the heart lie in terms of the diaphragm?
above
The base of the heart is which part of the heart? Top of bottom anatomically?
top
Where does the base lie?
beneath the 2nd rib
Where is the apex of the heart?
5th intercostal space
What is the covering of the heart called?
pericardium
Name the layers of the pericardium:
- Fibrous
- Visceral
- Parietal
Name the layers of the wall of the heart:
- epicardium
- myocardium
- endocardium
What does cardiac muscle have that is special?
striated, branched, intercalated discs, single nucleus
Describe the epicardium:
connective tissue, serous membrane - outer cover, secretes serous fluid
Describe the Myocardium
cardiac muscle tissue, contracts to pump blood from the heart chambers
Describe the Endocardium
membrane of epithelial that forms a protective inner lining of the chambers and valves
Where does blood enter the heart?
right atrium
Where does the heart receive blood (to be pumped to the body) from, what structures/vessels?
- inferior vena cava
- superior vena cava
- coronary sinus
Where does the heart tissue get blood for nourishment (not pump)?
- coronary arteries, branch of aorta
What is a heart attack?
MI, interruption of blood supply to the heart from a clot, death of cardiac cells,
What is a natural protection from heart attacks?
arterial anastomoses which provide alternate route of blood flow (collateral circulation)
What is chest pain from partial obstruction of coronary blood flow?
angina pectoris - ischemia of heart muscle, myocardium shifts to anaerobic fermentation, producing lactic acid and thus stimulating pain
Where does blood get sent in the pulmonary circuit?
oxygen-poor blood is sent to the lungs to get oxygen and unload co2
Can the heart be considered 1 or 2 pumps?
2 pumps
Where does the right side of the heart pump blood?
lungs (pulmonary circuit)
Where does the left side of the heart pump blood?
body (systemic circuit)
Where is the heart located in the thorax?
in the mediastinum, above the diaphragm
Where can you feel the apical heartbeat?
5th and 6th ribs to the left of the midline
What encloses the heart?
pericardium
What is the double layer serous membrane that covers the heart?
parietal and visceral pericardium
What is the fibrous pericardium made of?
dense connective tissue
What structures does the fibrous pericardium attach to?
sternum, vertebral column, diaphragm, heart blood vessels
What is the space between the parietal and visceral serous layers?
pericardial cavity
What is contained in the pericardial cavity?
serous fluid
What is the function of the serous fluid?
reduce friction between the pericardial membranes as the heart moves within them
What are the 3 distinct layers of the heart?
- epicardium
- myocardium
- endocardium (innermost)
What is the epicardium also known as?
visceral pericardium
Describe the epicardium:
- connective tissue and epithelium, lymph capillaries, nerve fibers, deeply layers have fat,
Describe the myocardium:
thick, cardiac muscle tissue that pumps blood, lymph capillaries, nerve fibers,
Describe the endocardium:
epithelium and connective tissue. many elastic and collagen fibers. Covers purkinjie fibers
What layer of the heart lines all the heart chambers and covers the structures such as the valves?
endocardium
Atria receive blood _______ (to) the heart. (returning/leaving)
returning
Atria have ______ that increase surface area:
auricles
Name the 2 septums in the heart:
interatrial septum (Separates atria) and interventricular septum (separates ventricles)
Through which structure does the atrium on each side communicate with the ventricle below it?
atrioventricular orifice
The AV orifice is guarded by what?
AV valve
There are also 2 sulci on the surface of the heart. Name them and what they separate:
- atrioventricular sulcus - separates atria and ventricles (encircles the heart - ring around the middle horizontally)
- interventricular sulci - separates ventricles
Where does the right atrium receive blood?
- superior vena cava
- inferior vena cava
- coronary sinus (from the myocardium of the heart)
Where does coronary sinus blood come from when it drains in the right atrium?
myocardium
When blood pressure is greater on the atrial side what happens to the tricuspid valve?
it folds out of the way to let blood flow to the ventricle (passively)
When blood pressure is greater on the ventricle side what happens to the tricuspid valve (right AV valve)
it closes to block backflow of blood (passively)
What are the strong fibrous strings called in the heart?
chordae tendineae
Where do the chrodae tendineae originate?
papillary muscles
When do the papillary muscles contract?
when the ventricles contract, preventing backflow. when the atria fill up and push blood to the ventricles, the AV valves are passivley open
Do the semilunar valves have chordae tendineae and papillary muscles?
NO! Only the AV valves have these structures
How many cusps do the semilunar valves have?
3
What constitutes the skeleton of the heart?
rings of dense connective tissue
Where does gas exchange occur in the lungs, after leaving the pulmonary trunk?
capillaries and air in the alveoli
REMEMBER: WHEN VALVES CONTRACT WHEN THE _____
VENTRICLE WALLS CONTRACT
What vessels supply blood to the heart?
left and right coronary arteries
Small branches of coronary arteries have connections (anastomoes) between vessels that provide alternate pathways for blood called ________.
collateral circulation.
Provide circulation when coronary artery is blocked
In most body parts, blood flow in arteries peaks during ___________.
ventricular contraction
Blood flow in the vessels of the myocardium is poorest during _________.
ventricular contraction. Muscle fibers of the myocardium compress nearby vessels as they contract, interfering with blood flow.
Contraction of the heart chambers is called:
systole
relaxation of the heart chambers is called:
diastole
Complete heartbeat is a cardiac ______.
cycle
Valves open due to ______
pressure differences
“Lubb-dubb” is due to:
vibrations in the heart tissues
heart sounds indicate the condition of _____
heart valves
lubb occurs during ____________.
ventricular systole
dubb occurs during ________.
ventricle diastole
What is it called when blood leaks back into valve:
murmur
What 2 vessels carry blood away from the heart?
arteries and arterioles
Which are thinner arteries or arterioles?
arterioles
Name the 3 layers of artery:
- tunica interna - simple squamous endothelium and connective tissue- can secrete substances to dilate or constrict blood vessels as well as prevent clotting
- tunica media - makes up bulk of wall, smooth muscle cells and connective tissue
- tunica externa - connective tissue with irregular elastic and collagen fibers
______ stimulate the smooth muscle to contract
vasomotor fibers
The walls of arterioles have 3 layers similar to arterioles but the middle and outer layers:
thin as approach the capillaries
Arterioles give off branches called _______ that join capillaries.
metarterioles
In some places metarterioles can connect directly with venous pathways without going through capillaries. these connections are called:
arteriovenous shunts
What are capillaries made of:
single layer of squamous epithelial cells
Capillaries in smooth, skeletal and cardiac muscle have _____ openings than capillaries in the kidneys, small intestine and endocrine glands.
smaller openings!
Capillaries with the largest openings include those of the: l
liver, spleen and red bone marrow
The higher a tissue’s rate of metabolism, the ______ its capillary networks:
denser
What is the name of the smooth muscle around capillaries:
precapillary sphincter
_____ is the most important means of transfer between the blood and tissue fluid.
diffusion
What type of substances can pass through capillary membranes?
lipid-soluble such as oxygen, co2 and others
How can non-lipid substances get through capillary membranes?
channels
What substances usually stay in the capillaries?
plasma proteins
Blood pressure is greater closer/farther to the heart
closer due to less friction
Plasma proteins create ______ pressure that draws water into capillaries.
osmotic
The term _____ _____ ______ describes this osmotic effect due to plasma proteins.
colloid osmotic pressure
What force helps filtration in capillaries?
blood pressure from constricting blood vessel walls
After arterioles drain to capillaries _____ attach.
venules
Veins have a larger/smaller lumen
larger
Veins can also function as blood _______, which are useful in times of blood loss.
reservoirs
