Cardiovascular system Flashcards
Cardiovascular system function (1)
Transport nutrients and metabolic waste VIA the blood
Cardiovascular system function (2)
Transport oxygen and carbon dioxide VIA the blood
Cardiovascular system function (3)
Transport hormones VIA the blood
Cardiovascular system function (4)
Transport heat VIA the blood
Pulmonary circuit
Delivers blood TO and FROM lungs for external respiration
Systemic circuit
Delivers blood TO and FROM rest of the body for internal respiration
Capillary beds
Where exchange takes place
Artery
Delivers blood FROM the heart BACK to capillary beds
Do arteries carry oxygenated blood?
Most arteries, not all
Veins
Deliver blood from capillary beds to new location
Where do most veins take blood back to?
Heart
Where do portal veins take blood?
To another capillary bed
What is the heart?
A muscular pump that circulates blood
What surrounds the heart?
Pericardial cavity in the mediastinum
What are the layers of the pericardium? (superficial to deep)
Fibrous pericardium (outer), parietal layer of serous pericardium, pericardial cavity (contains fluid), visceral layer of serous pericardium
Cardiac tamponade
Compression of the heart due to excess fluid in pericardial cavity
What are the layers of the heart’s wall? (outer to inner)
Epicardium, myocardium, endocardium
Epicardium
Visceral layer of serous pericardium (peri = perimeter/surrounds entire heart)
Myocardium
Cardiac muscle layer (thickest/in the middle)
Endocardium
Has simple squamous epithelium and lines inner heart (including valves)
Atria
Receives blood from veins
Atrium
Hall/pathway that connects places
Where does the right atrium receive deoxygenated blood from?
From inferior/superior vena cava and the coronary sinus
Where does the left atrium receive oxygenated blood from?
Pulmonary veins (two from right lung and two from left lung)
Ventricles
Eject blood from the heart
Where does the right ventricle pump deoxygenated blood to?
Pulmonary trunk and then pulmonary arteries
Where does the left ventricle pump oxygenated blood to?
Aorta (coronary arteries are branches of aorta) that supply blood to heart tissues
Heart valves
Prevent back flow of blood
Atrioventricular valves (AV valves)
Between atrium and ventricle
Tricuspid valves (R AV valves)
Between right atrium and ventricle
Bicuspid valves (mitral, L AV valve)
Between left atrium and ventricle
What hold valves in place?
Chordae tendineae which are anchored to papillary muscles
What do papillary muscles help with?
Preventing eversion (prolapse or leaking)
Semilunar valves (SL valves)
Between great arteries and ventricles
Aortic SL valve
Between left ventricle and aorta
Pulmonary SL valve
Between right ventricle and pulmonary trunk
What does the first heart sound “lub” mean?
Closing of both AV valves (WHEN LEFT AND RIGHT VENTRICLES BEGIN CONTRACTING)
What does the second heart sound “dup” mean?
Closing of both SL valves (WHEN LEFT AND RIGHT VENTRICLES BEGIN RELAXING)
How does the conducting system relate to intrinsic rhythm?
Has specialized cardiac muscle cells which initiate electrical signal to the heart chamber to contract
How does the signal to the heart chambers spread from one cardiac muscle cell to another?
Gap junctions
What is the sequence of conduction?
Sinoatrial node, atrioventricular node, bundle of His, bundle branches, purkinje fibers
Sinoatrial node (SA node)
Pacemaker that has the fastest spontaneous fire
Purkinje fibers
Subendocardial conducting network (runs up walls of heart)
Heart block
Damage to AV node or bundle of His (only path from atria to ventricles)
What happens during heart block?
Signal never reaches ventricles, they still beat but at a slower pace
What is the solution for heart block?
Artificial pacemaker restores normal function
Is blood a type of connective tissue?
Yes
What are the components of blood?
Plasma, erythrocytes, leukocytes, platelets
Plasma
Fluid with dissolved nutrients, etc.
Erythrocytes
Red blood cells that carry oxygen
Leukocytes
White blood cells that act as immune cells
Platelets
Cell fragments for clot formation
What are in blood vessels?
Capillary, artery, vein
Capillary
Allows diffusion between blood and tissues
Artery
Carries blood away from heart
Vein
Carries blood away from capillary beds and back to heart eventually
What is the general structure of the blood vessel wall?
Tunica intima, tunica media, tunica externa
Tunica intima
Has endothelium (simple squamous epithelium)
Tunica media
Has smooth muscle, collagen, elastin, circularly arranged
Tunica externa
Has collagen, elastin, longitudinally arranged
How is the artery structure compared to veins and capillaries?
Subject to higher pressure, thick walls (high elastin), and more elastic
Elastic arteries
Largest arteries (1cm to 1inch), thick wall, very elastic for smoothing out pressure fluctuations
Muscular arteries
Most named arteries, (0.3mm to 1cm), thickest tunica media relative to vessel diameter, regulate bp and distribution
Arterioles
Smallest arteries (0.01 to 0.3mm), regulate bp and distribution
What does the capillary structure do?
Facilitate diffusion
What tunica do capillaries have?
Tunica intima (mostly endothelium), very thin wall
What are the size of capillaries and what are some other characteristics?
<0.01mm wide, all blood in capillary is close to the wall, large surface area
Capillary beds (when tissue is active)
Arterioles dilate, blood flows into capillaries, exchange occurs
Capillary beds (when tissue is not active)
Arterioles constrict, shuts off blood flow and exchange
Which capillary beds use precapillary sphincters and what for?
Mesenteric capillary beds use them to control blood flow into capillaries
What are the types of capillary beds?
Continuous capillaries, fenestrated capillaries, sinusoid capillaries
Continuous capillaries (in brain)
Completely sealed by tight junctions, all molecules must go across membrane of endothelial cell, least leaky (blood brain barrier)
Continuous capillaries (in most organs)
Not completely sealed by tight junctions (somewhat leaky), small molecules can pass through intercellular clefts
Fenestrated capillaries
Have fenestrations (holes thru endothelial cells), allows more rapid exchange of small molecules, (INCLUDE kidney, endocrine glands, intestines, synovial membranes)
Sinusoid capillaries
Have fenestrations, very few tight junctions, allows exchange of proteins and cells (fluidy), (INCLUDES liver, lymphoid organs like spleen and red bone marrow)
Vein structure (1)
VERY low pressure system
Vein structure (2)
Thinner walls than arteries, less smooth muscle/elastin, collapsible
Vein structure (3)
Larger lumen than arteries, blood reservoir, ~65% of total body blood
Vein structure (4)
Have valves to prevent back flow of blood
What are the types of veins?
Venules, veins, portal veins
Venules (small veins)
Receive blood from capillaries
Veins (other than venules)
Receive blood from venules
Portal veins
Deliver blood from capillary bed to capillary bed (middle man of circulation/exchange)
What is an example of a portal vein?
Hepatic portal vein
Mechanism for enhancing venous return (1)
Return of blood to the right side of the heart
Mechanism for enhancing venous return (2)
Return is slow because of low pressure
Mechanism for enhancing venous return (3)
Needs a way to enhance blood return to heart
Example of speeding of venous return
Skeletal muscle pump allows for the pressure to change (and valves) which drives blood back to heart