What is a fenestrated capillary?
- More permeable than continuous capillaries
- Function in absorption or filtrate formation (small intestines, endocrine glands and kidneys)
- Are not found in the brain
Why is the left ventricular heart wall thicker than the right?
It helps it pump blood with greater pressure
What happens with a thromboembolic disorder?
Involves embolus formation, a clot moving throughout the circulatory system
Which blood type is a universal donor?
What are functions of myocardial cells?
The entire heart contracts as a unit or it does not contract at all
What events occur when the semilunar (SL) valves are open?
- Blood enters pulmonary arteries and aorta
- AV valves are closed
- Ventricles are in systole
What epithelia supports the tunica intima?
Squamous epithelium supported by a sparse connective tissue layer
What are three main factors influencing blood pressure?
- Cardiac output (CO)
- Peripheral resistance
- Blood volume
What are the parts of the heart's conducting system?
- AV node
- SA node
- Bundle of His
What regulates cerebral blood flow?
Intrinsic autoregulatory mechanisims
What is the source of blood going to capillaries in the myocardium?
Also called thrombocytes, stick to area of damaged blood vessel and help to seal the break
What is caused by hemorrhaging and a large loss of blood?
A lowering of blood pressure due to a change in cardiac output
What is the plasma protein that is a main contributor of osmotic pressure?
Blood flow through the vascular system is equal to?
What is an isovolumetric contraction?
The short period during ventricular systole when the ventricles are completely closed chambers
What is the primary function of capillaries?
Permitting the exchange of nutrients and gases between the blood and tissue cells
What are some protective functions of blood?
Clotting, presence of white blood cells and contains antibodies and antigens
What are sinusoids?
Modified capillaries that are lined with phagocytes
Peripheral resistance increases as what else increases?
Where in the body is blood flow velocity the slowest?
In the capillaries because the total cross-sectional area is the greatest
Blood is what type of substance?
What are some functional characteristics of WBC?
What is the slowest step in the clotting process?
Formation of prothrombin activator
Blood in pulmonary veins returns to where?
Some basic facts about heart valves
AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.
What vessels receive blood during ventricular systole?
Aorta and pulmonary trunk
The tunic of an artery most responsible for maintaining blood pressure?
What organ regulates red blood cell production?
What layer of the heart contracts?
Where do arteries carry blood in regards to the heart?
All carry blood away from the heart
What is the most common type of blood capillary?
When does blood flow increase to skin?
When environmental temperature increases
What is hypovolemic shock?
Shock that results from large-scale loss of blood volume, or after severe vomiting or diarrhea
What would happen to heart rate if vagal nerves to the heart were cut?
The heart rate would increase by about 25 beats per minute
What is a blood pressure reading indicative of hypertension?
What is pernicious anemia?
A lack of intrinsic factor, leading to a deficiency of vitamin B12
and large pale cells called
Aldosterone does what to blood pressure?
Promotes an increase
What influence does blood vessel diameter have on peripheral resistance?
A significant amount because resistance is inversely proportional to the fourth power of the vessel radius
What is cardiac tamponade?
Pressure on the heart that occurs when blood or fluid builds up in the space between the heart muscle (myocardium) and the outer covering sac of the heart (pericardium).
Some factors influencing heart rate
Age, gender and body temperature
In an EKG, the P wave is indicative of what?
A thrombus in the first branch of the arch of aorta would affect blood flow to where?
Right side of the head and neck and right upper arm
What is the cause of bleeding disorders?
Thrombocytopenia, a condition of decreased circulating platelets, a defect in the clotting cascade and/or vitamin K deficiency
Explain Angina Pectoris
A man enters the hospital complaining of chest pain. His history includes smoking, a stressful job, a diet heavy in saturated fats, lack of exercise, and high blood pressure. Although he is not suffering from a heart attack, his doctor explains to him that a heart attack is quite possible. What did the chest pain indicate? Why is this man a prime candidate for further complications?
Angina pectoris. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of oxygen, resulting in a heart attack. Patient should refrain from smoking and improve diet..
Increase in red blood cell production would cause what effect on blood pressure?
Excess red cell production would cause a blood pressure increase
If blood supply is stopped to a cardiac muscle, damage results from what?
Decreased delivery of oxygen
What are some factors that trigger erythropoiesis?
Hypoxia of EPO-producing cells
What heart vessels receive blood during right ventricular systole?
Phases of hemostasis
- Vascular spasm: vasoconstriction of damaged blood vessels
- Platelet plug formation: platelets stick to collagen fibers via plasma protein, swell and become spiked, releases chemical messages
- Coagulation: reinforces platelet plug with fibrin threads, blood transformed from liquid to gel
What are muscular arteries?
During ventricular filling, where does blood flow?
Blood flows passively through the atria and the open AV valves into the ventricles
Some age-related factors affecting the heart
- Decline in cardiac reserve
- Fibrosis of cardiac muscle
What influences arterial pulse rate?
- Postural changes
When is the tricuspid valve closed?
When the ventricle is in systole
What are veins also known as?
During vigorous exercise, capillaries will do what?
Capillaries of the active muscles will be engorged with blood
What is the foramen ovale?
Connects the two atria in the fetal heart
What are some distributive functions of blood?
- transport of metabolic wastes from cells
- transport of hormones to their target organs
- delivery of oxygen to body cells
A patient with blood type AB can receive what types of blood?
Can receive any blood type in moderate amounts except that with the Rh antigen
Facts about cardiac output
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction
Characteristics of all white blood cells
- Have nuclei and do not contain hemoglobin
- Average 5,000 - 9,000
- Can be granular or agranular
Why are arterioles known as resistance vessels?
The contraction and relaxation of the smooth muscle in their walls can change their diameter
How does norepinephrine act on the heart?
It causes the threshold to be reached more quickly
What parts of the heart are directly involved in pulmonary circulation?
Right ventricle, pulmonary artery, and left atrium
Why would you want low capillary pressure?
- Capillaries are fragile and high pressures would rupture them
- Most capillaries are extremely permeable and thus even low pressures force solute-containing fluid out of the bloodstream
What causes a heart block?
Damage to the AV node
What is a normal hemoglobin count?
Around 16 g/mL
Which arteries feed directly into capillary beds?
What would happen if the absolute refractory period in cardiac muscle cells was the same as in skeletal muscle?
Tetanic contractions might occur, which would stop the heart's pumping action
What distinguishes the left from right ventricle?
The left ventricle wall is thicker than the right
No visible cytoplasmic granules are present in what?
What is the most critical source of blood resistance?
Blood vessel diameter
What is the ductus venosus?
A special fetal vessel that allows umbilical blood to bypass the liver
What is a late sign of hypovolemic shock?
Rapidly falling blood pressure
When would brain blood flow autoregulation stop?
Abnormally high CO2 levels are present
What chemicals help regulate blood pressure?
- Atrial natriuretic peptide
- Angiotensin II
What is angina pectoris?
Pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries
What is renal regulation?
Provides a long-term response to changes in blood pressure
What type of muscle has gap junctions?
he disease process involves several stages and usually affects the aorta and coronary arteries. The initial event involves damage to the tunica intima caused by bloodborne chemicals or physical factors such as a blow or infection. Injured endothelial cells release chemicals that increase the uptake by the endothelium of fats, LDLs, and cholesterol. This eventually attracts macrophages that ingest the oxidized fats and, along with smooth muscle cells from the tunica media, transform into foam cells. Foam cells become fatty streaks, which, along with collagen and elastin fibers secreted by smooth muscle cells, form atherosclerotic plaques. These protrude into the lumen and narrow the blood vessels.
What is the largest constituent of blood plasma?
Water, about 90%
What is the hemocytoblast?
Hematopoietic stem cells
What is responsible for normal heart sounds?
Closure of the heart valves
What is pulse pressure?
Systolic pressure minus diastolic pressure
What makes up blood type O?
Type O blood has A and B Antibodies and NO ANTIGENS
What does blood type AB+ mean?
There are no antibodies to A, to B, or to Rh antigens in the plasma
The normal pH range of blood?
Where would you auscultate the aortic SL valve?
Second intercostal space to the right of the sternum
Explain Angina Pectoris
Blockage of the coronary arterial circulation can be serious and sometimes fatal. Angina pectoris is thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium. It may result from stress-induced spasms of the coronary arteries or from increased physical de- mands on the heart. The myocardial cells are weakened by the temporary lack of oxygen but do not die.
In arteriosclerosis, the walls
of our arteries become thicker and
stiffer, and hypertension results. In atherosclerosis, the most common
form of arteriosclerosis, small patchy thickenings called atheromas form that can intrude into the vessel lumen, making it easy for arterial spasms or a roaming blood clot to close the vessel completely.