BIO148 Chapter 42
How does the sympathetic response regulate heart rate and blood pressure?
"Fight or Flight"; Increases heart rate and cardiac contraction; increases respiratory rate; increases blood flow to muscle and decreases flow to gut
How does the parasympathetic response regulate heart rate and blood pressure?
"Rest and Digest"; decreases heart rate and cardiac contraction;
What role do gap junctions play in the heart?
Allowing synchronous beats
What are the three main types of blood vessels?
Arteries, veins, capillaries
What are their major characteristics?
Arteries: carry oxygenated blood to the body, high pressure, 3 layers (intima: endothelium, media: smooth muscle, adventitia: mostly connective tissue, contains sympathetic nerves); branch into arterioles and carry blood to capillaries; Veins: return de-oxygenated blood to the heart, low pressure, less smooth muscle and elastin fibers, have valves that prevent backflow, venules converge into veins and return blood from capillaries to the heart Capillaries: gas and nutrient exchange with tissues/cells happens in the capillaries, capillary beds connect arteries to veins, single layer of epithelium, capillary beds (network of capillaries) are the site of chemical exchange between blood and interstitial fluid (fluid that surrounds cells in the body),
What happens in the case of a stroke?
Atherosclerosis of cerebral (brain) arteries; rupture or blockage of blood flow, death of nervous tissue, sudden death or permanent neurological damage
What happens in the case of a heart attack?
Atherosclerosis of coronary arteries; partial to complete block of blood flow, death of cardiac muscle, sudden death or permanent cardia damage
What are the four valves of the heart? What do they connect?
Atrioventricular valves (between atria and ventricles): Tricuspid: connects right atrium to ventricle Mitral (Bicuspid): connects left atrium to ventricle Semilunar valves (prevents back flow of blood, at the base of the aorta and the pulmonary artery): Pulmonic Aortic
What is the site of gas and nutrient exchange in the cardiovascular system?
Capillary
What is atherosclerosis?
Caused by buildup of plaque deposits within arteries
What are the three main components to a circulatory system?
Circulatory fluid (blood), set of tubes (blood vessels), muscular pump
How are cardiomyocytes unique?
Connected by gap junctions
What are continuous capillaries?
Continuous capillaries: endothelial cells joined by tight junctions
What is bradycardia?
Decrease in heart rate; less than 60 beats per minute
What are fenestrated capillaries?
Fenestrated capillaries: have small holes or fenestrations that allow for more/rapid movement of small particles
How many chambers does the human heart have?
Four-chambered heart
How is O2 transported to tissues?
Gases diffuse across alveoli
How is fetal hemoglobin different, structurally and functionally?
Hemoglobin has 4 subunits (2 alpha, 2 beta) and while fetal hemoglobin has 4 subunits they are 2 alpha and 2 gamma which has a higher affinity to bind to O2
What is hypertension?
High blood pressure, promoted by atherosclerosis, increases risk of heart attack and stroke
What is tachycardia?
Increase in heart rate; more than 100 beats per minute
What is anemia?
Insufficient red blood cells (RBCs) which causes a decreased ability to carry O2 which causes blood loss (hemorrhagic, RBC lysis (hemolytic), decreased production of PBCs
Compare and contrast the right and left sides of the heart.
Left: pumps and receives only oxygen-rich blood Right: receives ad pumps only oxygen-poor blood
What is the main function of a circulatory system?
Link exchange surfaces with cells throughout body
What does an ECG measure?
Measures electrical conduction of the heart
How does the circulatory system interact with other systems?
Most complex animals have internal transport systems that circulate fluid
What is valvular stenosis?
Narrowing; valve does not open properly, blood flow through valve decreases; causes developmental malformations or aging which causes calcium build up on valves
How does airflow through the system?
Nostrils to pharynx to larynx to trachea to bronchi to bronchioles to alveoli
Compare an open to a closed circulatory system. What do humans have?
Open: Blood bathes the organs directly, no distinction between blood and interstitial fluid (general body fluid called hemolymph), found in arthropods and most molluscs Closed: Blood is confined to vessels and distinct from the interstitial fluid (fluid and molecules can leave and return in response to pressure), more efficient at transporting circulatory fluids to tissues and cells
What pressure causes fluid to re-enter at the venule end of the capillary?
Osmotic pressure
What pressure causes fluid to move out at the arterial end of the capillary?
Outward flow
What is polycythemia?
Overload of RBCs which causes increased ability to carry O2 and increased velocity which causes decreased blood flow which causes organ damage/death; causes renal artery stenosis (kidneys sense decreased O2 delivery which causes increases EPO production) and exogenous erythropoietin (EPO) injection
What are the 3 major components shown on an ECG diagram? What do they represent?
P wave: atrial contraction QRS complex: ventricular contraction T wave: ventricular relaxation
What are the components of blood?
Plasma: 50-60% of volume Cellular components: 40-50% of volume
What binds O2 in the RBC?
RBCs contain hemoglobin that binds to CO2
What are the two types of pacemaker cells?
SA (sinoatrial) node cells, AV (atrioventricular) node cells
How do pacemaker cells work to contract the heart?
SA node cells: contracts atria and send signal to AV node. AV node cells: send signals down the Bundle of His and ventricles contract
What are platelets? What process are they involved in?
Small cell fragments that help blood clot after injury; blood clotting (endothelium damaged which activates clotting mechanism which changes fibrinogen to fibrin and fibrin clots blood) and excessive clotting can lead to thrombus formation (thrombus is a blood clot which can block blood flow)
What is the function of the respiratory system?
Supplies oxygen and disposes of carbon dioxide
How is a blood pressure measurement written?
Systolic/diastolic
What is systolic blood pressure versus diastolic blood pressure? What do they represent?
Systolic: blood pressure during systole (ventricular contraction) Diastolic: blood pressure during diastole (ventricular relaxation)
What anchors the atrioventricular valves?
They attach to the cusp of the atrioventricuar valves via the chordae tendinae
What is the function of red blood cells (RBCs)?
To carry O2 an CO2
What are the functions of blood?
Transport oxygen, carbon dioxide, nutrients, wastes, hormones, immune cells and help regulate pH and temperature
What are the chambers called and what are their functions?
Two upper chambers (atria) and two lower chambers (ventricle) "pump" enters through atria and exits through ventricle
What is valvular insufficiency?
Valve does not close properly, allowing back flow; causes are post heart attack or rheumatic fever (autoimmune disease in which antibodies attack valves)