Exam 1 Study Guide Flashcards
Describe homeostasis.
Homeostasis is the presence of a stable internal environment.
What are the components of a feedback loop?
Receptor/ Control Center/ Effector
The components of a feedback loop are a receptor (or sensor that is sensitive to a particular environmental change or stimulus), control center (or integration center which receives and processes the information supplied by the receptor and which sends out commands), and an effector (which responds to the command by opposing the stimulus)
Be able to differentiate between positive and negative feedback.
Positive feedback – an initial stimulus produces a response that exaggerates or enhances the change in the original conditions rather than opposing it
Negative feedback – the primary mechanism of homeostatic conrol; a corrective mechanism that opposes or negates a variation from normal limits
What are the formed elements of blood?
Formed elements are blood cells and cell fragments suspended in plasma, they are; platelets, red blood cells (RBCs), and white blood cells (WBCs).
What is the function of platelets?
Platelets are small, membrane bound cellf ragments that contain enzymes and other substances important to blood clotting.
What is the function of RBCs?
RBCs (aka erythrocytes) are the most abundant blood cells. These specialized cells are essential for oxygen transport in the blood
What is the function of WBCs?
WBCs (aka leukocytes) play a role in the body’s defense mechanisms. There are five classes of leukocytes, each with slightly different functions.
What are the main solutes in blood plasma?
Plasma proteins 7% (albumins, globulins, fibrinogen)
Other solutes 1% (electrolytes, organic nutrients, organic wastes)
Water 92%
What are the functions of albumins? (plasma protein)
Albumins: make up about 60% of the plasma proteins. As the most abundant plasma proteins, they are major contributors to the osmotic pressure of plasma.
What are the functions of globulins? (plasma protein)
Globulins: make up approximately 35% of the proteins in plasma. Important plasma globulins include antibodies and transport globulins. Antibodies, also called immunoglobins, attack foreign proteins and pathogens. Transport globulins bind small ions, hormones, lipids, and other compounds.
What are the functions of fibrinogens? (plasma protein)
Fibrinogen: functions in clotting and normally makes up about 4 percent of plasma proteins. Under certain conditions, fibrinogen molecules interact to form large, insoluble strands of fibrin that form the basic framework for a blood clot.
What are the functions of electrocytes? (other solutes in whole blood)
normal extracellular ion composition is essential for vital cellular activities
What are the functions of organic nutrients? (other solutes in whole blood)
nutrients are used for ATP production, growth, and cell maintenance
What are the functions of organic wastes? (other solutes in whole blood)
wastes are carried to sites for breakdown or excretion
What is the difference between plasma and serum?
plasma: the fluid ground substance of whole blood; what remains after the cells have been removed from a sample of whole blood
serum: the ground substance of blood plasma from which clotting agents have been removed
What is a hematocrit?
-the hematocrit is the percentage of formed elements in a sample of whole blood; red blood cells make up 99.9% of formed blood cells
Have a basic understanding of hematopoiesis. Where does hematopoiesis take place?
Blood cell formation is called hematopoiesis and takes place in the red bone marrow
What do the lymphoid stem cells give rise to?
Lymphoid stem cells: responsible for the production of lymphocytes, originate in the red bone barrow (some remain in the red bone marrow, others migrate to lymphoid tissues such as thymus, spleen, and lymph nodes)
Relate the structure of red blood cells with their function.
The biconcave shape of red blood cells allow for;
- large surface area to volume ratio
- RBCs are able to form stacks
- flexibility for entering small capillaries and branches
What is hemoglobin?
A protein composed of four globular subunits, each bound to a heme molecule; gives red blood cells the ability to transport oxygen in the blood.
Why do red blood cells last only 120 days?
As RBCs develop, they lose most of their organelles, including nuclei. Mature RBCs lack nuclei and they lack ribosomes so they cannot divide or synthesize structural proteins or enzymes. Because of this; they cannot repair themselves and have a life span of 120 days or less.
How do you calculate a hematocrit?
Hematocrit is measured by packed cell volume (PCV); this is the percentage of blood occupied by RBCs. This can be done by a blood test called CBC.
Why do males generally have a higher hematocrit?
The difference in hematocrit between sexes primarily reflects the fact that androgens (male hormones) stimulate RBC production, where as estrogens (female hormones) do not.
male average 47
female average 42
What are the five types of leukocytes (WBCs)?
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
How is hemoglobin recycled and where specifically does it take place?
The breakdown of erythrocytes starts with phagocytosis of red blood cells by Kupffer cells. Kupffer cells break down hemoglobin into globin and iron-containing heme groups. Heme groups are broken down into iron and bile. Iron can be transported to the bone marrow (where new hemoglobin is produced) within the protein transferrin. Iron is carried to the bone marrow to produce hemoglobin in new red blood cells
Define erythropoiesis
Erythropoiesis is the formation of red blood cells
Define anemia.
Anemia is a condition in which the blood has a low O2 carrying capacity
What are the potential causes of anemia?
blood loss, iron deficiency, lack of red blood cells
Describe the A/ B/ AB/ O blood groups.
Type A blood has RBCs with surface antigen A only; plasma contains anti-B antibodies.
Type B blood has RBCs with surface antigen B only; plasma contains anti-A antibodies.
Type AB blood has RBCs with both A and B surface antigens; plasma contains neither anti-A or anti-B antibodies.
Type O blood has RBCs without A or B surface antigens; plasma contains both anti-A and anti-B antibodies.
What blood type is the universal donor?
O-
What blood type is The universal recipient?
AB+
What causes the mother to develop Rh antibodies?
A mother develops Rh antibodies because ant-Rh antibodies are able to pass through the placenta and enter the fetal blood stream.
Be familiar with the different types of white blood cells and their functions.
Neutrophils - phagocytic; engulf pathogens or debris in injured or infected tissues; release cytotoxic enzymes and chemicals
Eosinophils - phagocytic; engulf antibody-labeled materials; release cytotoxic enzymes; reduce inflammation; increase in abundance in allergies and parasitic infections
Basophils - enter damaged tissues and release histamine and other chemicals that promote inflammation
Monocytes - enter tissues and become macrophages; engulf pathogens or debris
Lymphocytes - cells of the lymphatic system; provide defense against specific pathogens or toxins
What does a differential white blood cell count tell you?
A blood differential count measures the relative numbers of each of the WBC subtypes in the blood; values reported indicate the number of each type of cell in a sample of 100 WBCs.
A differential count also includes information about abnormal cell structure and the presence of immature cells.
How are leukocytosis and leukopenia different?
leukocytosis: increase in WBCs
leukopenia: reduction in WBCs
Define hemostasis.
Cessation of bleeding in a quick and localized fashion when blood vessels are damaged
What are the three primary mechanisms that help reduce blood loss?
Vascular spasm
Platelet plug formation
Coagulation
What are the three major steps of coagulation?
Coagulation or clotting occurs in three phases:
1: Two pathways lead to prothrombin activator.
2: Common pathway to thrombin.
3: Common pathway to the fibrin mesh
What are the differences between the extrinsic and intrinsic pathways?
extrinsic pathway - a clotting pathway that begins with damage to blood vessels or surrounding tissues and ends with the formation of tissue factor complex
intrinsic pathway - a pathway of the clotting system that begins with the activation of platelets and ends with the formation of factor X activator complex
What is the role of Vitamin K in blood clotting?
Normal clotting requires adequate vitamin K; required for synthesis of 4 clotting factors by hepatocytes; produced by bacteria in large intestine
What is fibrinolysis? What is the role of plasmin?
The process of a clot gradually dissolving.
Fibrinolysis begins with the activation of the proenzyme plasminogen by thrombin, produced by the common pathway, and tissue plasminogen activator released by damaged tissues. The activation of plasminogen produces the enzyme plasmin which erodes the foundation of the clot.
How do RBCs, WBCs and platelets compare with respect to the number per microliter of blood and life span?
45% of blood volume is formed elements:
RBCs (4.8-5.4 million per microliter; 120 days)
WBCs (5,000-10,000 per microliter; 60-70% are neutrophils; life span varies)
Platelets (150,000-400,000 per microliter; 9-12 days)
Describe the functions of the cardiovascular system.
Transport blood, oxygen, CO2, hormones, and proteins
Describe the structure of the pericardium.
The pericardium is the covering of the heart. Consists of fibrous and serous.
Fibrous - outer, tough, inelastic
Serous - two layers; parietal, visceral; and pericardial cavity (reduces friction)
What is the relationship between wall thickness and function of the chambers of the heart.
Thickness of cardiac walls; ventricles pump the same amount of blood but the left side pumps at a much higher pressure in order to reach the rest of the body therefore the wall of the left ventricle is much thicker
Describe the structure and function of the heart valves.
Heart valves establish unidirectional flow of blood; two types of valves - atrioventricular and semilunar.
Discuss the coronary circulation. Make sure that you know the major arteries.
Coronary circulation is blood supply to the heart. When the heart relaxes, the high pressure of blood in the Aorta pushes blood into coronary vessels.
L and R coronary arteries; Anterior interventricular artery; Posterior interventricular artery; Circumflex artery
How do cardiac muscle fibers differ structurally and functionally from skeletal muscle fibers?
Myofibrils are short and fat but they branch extensively; The ends of the cells form unions with each other via intercalated discs which contain desmosomes and gap junctions; These intercalated discs allow the heart to behave as a single unit; Each fiber contains one or at the most two large, centrally located nuclei; About 25% of the total volume of cardiac fibers is large mitochondria vs 2% in skeletal muscle.
Why can’t cardiac muscle fibers undergo tetanus?
Because they have a longer refractory period.
What does it mean when it is said that the heart exhibits automaticity?
The cardiac cell’s ability to spontaneously generate an electrical impulse;
What are the autorhythmic cells of the heart?
Often referred to as the pacemaker cells because they are responsible for synchronizing the contractile cells to coordinate a heart contraction.
In what ways are these autorhythmic
cells different from the contractile cells?
Autorhythmic cells only initiate and synchronize electrical stimulation; contractile cells are only responsible for pumping blood.
Describe the components of the intrinsic conduction system in the heart.
SA node, AV node, AV bundle, Bundle branches, Purkinjie fibers
Where is the pacemaker of the heart located?
SA node
Why is there a delay between the contraction of the atria and the ventricles?
This allows time for blood to completely leave Atria before contraction of the ventricles.
What is the difference between systole and diastole?
Systole is the contraction and emptying of the chamber. Diastole is the relaxing and filling of the chamber.
At the beginning of ventricular diastole, the ________ valves are open and the ______ valves are closed. This is the exact opposite during ventricular systole when the ________ valves are closed and the ________valves are open.
Av valves; Semilunar valves - - - AV valves; Semilunar
Define end-systolic and end-diastolic volumes.
end systolic: the amount of blood present in ventricles after contraction
end diastolic: the amount of blood present in ventricles before they relax
The recording of the electrical changes in the heart is called ____________________.
electrocardiogram (ECG or EKG)
What is cardiac output? How is it calculated?
the amount of blood pumped out each ventricle each minute
CO = SV x HR
Define stroke volume and explain the factors that regulate it?
Volume of blood pumped with each contraction of the heart. Factors that regulate it are End Diastolic Volume, Contractility, length tension relationship or optimal zone of overlap caused by blood in the ventricles.
What is the Frank-Starling law of the heart?
increasing the length of cardiac muscle fibers can produce dramatic increases in contractile force (SV)
Explain how the autonomic nervous system adjusts heart rate.
The sympathetic nervous system raises HR using epinephrine to stimulate the pacemaker cell. Parasympathetic nervous system decreases the HR via the vagus nerve by hyperpolarizing the pacemaker cell.
Describe the three layers that typically form the wall of a blood vessel.
Tunica interna (intima) - found in the endothelium and basement membrane Tunica media - found in elastic fibers, collagen and circular smooth muscle Tunica externa (adventitia) - found in collagen and elastic fibers
Understand the specific roles of each blood vessel type.
There are five general classes of blood vessels in the cardiovascular system:
Arteries - carry blood away from the heart and towards a peripheral cavity.
Arterioles - smallest arterial branches.
Capillaries - small blood vessel where diffusion occurs between blood and interstitial fluid.
Venules - collect blood from capillary beds and are the smallest venous vessel
Veins - a blood vessel carrying blood from the capillary bed towards the heart
Define vasoconstriction.
vasoconstriction: a decrease in the diameter of arterioles due to the contraction of smooth muscles in the tunica media; increases peripheral resistance; may occur in response to local factors, through the action of hormones, or from the stimulation of the vasomotor center
Define vasa vasorum.
vasa vasorum is a network of small blood vessels that supply the walls of large blood vessels such as elastic arteries and large veins
Structurally how do veins differ from arteries?
- Walls of arteries are thicker than those of veins
- Tunica Media - Arteries contain more smooth muscle and elastic fibers
- Veins have a larger lumen
- Valves presents in veins
Name the three types of capillaries. Where are they found?
Continuous (skin and muscles)
Fenestrated (kidneys, median eminence)
Sinusoids (liver, red bone marrow)
Describe the structure and function of a capillary bed.
Structure: two types of vessels; metarteriole and true capillaries
Capillaries are grouped together in capillary beds, which are simply a network of capillaries. Capillary beds are too small to see, but if you could see them, they would look like endless alleyways leading to virtually every tissue in your body. The rate of blood flow within a capillary bed is slow because there are so many different alleyways through which blood can travel. This slow speed limit, along with the very thin walls of the capillaries, means that capillary beds are an ideal place for the exchange of gases, nutrients, hormones and wastes between the blood and tissue cells.
How does one calculate the mean arterial blood pressure?
Mean Arterial Blood Pressure = diastolic pressure + 1/3 (pulse pressure)
What is the difference between systolic and diastolic blood pressure?
systole = contracting and emptying diastole = relaxing and filling
How do substances enter and leave capillaries?
Substances move in and out of the capillary walls as the blood exchanges materials with the cells.
The thin walls of the capillaries are composed of a single layer of endothelial cells. As a result, gasses such as oxygen and carbon dioxide can diffuse through their walls, as can lipid soluble substances.
Describe the two primary forces that determine bulk flow through the capillary membrane.
blood hydrostatic pressure DESCRIBE
blood colloid osmotic pressure DESCRIBE
What is the role of bulk flow?
Bulk flow across the capillary wall is important in extracellular fluid distribution; helps in the short term regulation of blood pressure
Define venous return.
The amount of blood arriving at the right atrium each minute. On average it is equal to the cardiac output.
Name two factors that aid in venous return.
Increased sympathetic activity
Muscular compression
Why must blood pressure be regulated?
Must be high enough to ensure sufficient
driving pressure; Pressure must not be so high that it creates extra work for the heart and increases the risk of damage to blood vessels
Define autoregulation of blood flow and give several examples of chemical factors involved?
Autoregulation of blood flow is the tendency for blood flow to remain constant despite changes in arterial perfusion pressure.
Chemicals that increase BP - Adrenal medulla hormones (norepinephrine and epinephrine); ADH
Chemicals that decrease BP - ANP; NO; inflammatory chemicals, alcohol
Describe the response of the baroreceptor reflex mechanism to changes in blood pressure.
The baroreceptor reflex is activated whenever blood pressure increases or decreases. The reflex is somewhat more sensitive to decreases in pressure than to increases, and is more sensitive to sudden changes in pressure than to more gradual changes. Sensory stimuli from baroreceptors in the carotid sinus and the aortic arch, acting via control centers in the medulla oblongata, affect the activity of sympathetic and parasympathetic nerve fibers in the heart.
What is auscultation?
the act of listening to sounds within the body
Insulin is fat-soluble. True/False
False.
Insulin is water-soluble.
Blood hydrostatic pressure is sometimes called
Capillary hydrostatic pressure
What is a desmosome?
anchoring junction
What is a gap junction?
similar to a pore, it allows ions and molecules to pass quickly between adjoining cells
What is the spread of cardiac excitation?
SA node; AV node; Bundle of His; Bundle branches; Purkinje fibers
What makes up whole blood?
Formed elements = 45% of whole blood/ Plasma = 55% of whole blood.
What do the myeloid stem cells give rise to?
give rise to all types of formed elements other than lymphocytes
Breakdown hemoglobin.
The protein globin is bound to the heme pigment. The globin portion of the molecule consist of four polypeptide chains, each bound to a heme group. Each heme group has an iron atom that can bind reversibly one molecule of oxygen. Thus, a hemoglobin molecule can bind up to four molecules of oxygen.
Define vasodilation.
vasodilation: an increase in the diameter of arterioles due to the relaxation of smooth muscles in the tunica media; decreases peripheral resistance; may occur in response to local factors. through the action of hormones, or after decreased stimulation of the vasomotor center
What are five functions of blood?
- Transporting dissolved gases, nutrients, hormones, and metabolic wastes
- Regulating pH and ion composition of interstitial fluids
- Preventing fluid loss at injury sites
- Defending the body against toxins and pathogens
- Regulating body temperature by absorbing and redistributing heat
State the function of the tunica intima.
also known as the tunica interna;the innermost layer of a blood vessel; includes the endothelial lining and an underlying layer of connective tissue containing elastic fibers
State the function of the tunica media.
also known as the middle layer; contains concentric sheets of smooth muscle tissue in a framework of loose connective tissue; when these muscles contract the vessel decreases in diameter
State the function of the tunica externa.
also known as the tunica adventitia; is a connective tissue sheath. In arteries, this layer contains collagen fibers with scattered bands of elastic fibers; in veins, it is generally thicker than the tunica media and contains networks of elastic fibers and bundles of smooth muscle cells
Why is it so important to determine the blood type of both the donor and recipient before blood is transfused?
If surface antigens on RBCs of one blood type re exposed to the corresponding antibodies from another blood type, the RBCs will clump together (agglutination) or undergo hemolysis. If either agglutination or hemolysis occur, the clumps or fragments of RBCs can plug small blood vessels in the kidneys, lungs, heart, or brain.
State the function of pericardium.
Prevents overstretching, reduces friction, anchors the underlying structures
Describe the heart wall.
The heart wall has three layers;
epicardium - the outside layer that is the visceral layer of the serous pericardium
myocardium - heart muscle; makes up the bulk of the wall
endocardium - inner surface of the heart; simple squamous epithelium
State the function of semilunar valves.
Backflow of blood into the heart as ventricles relax fills the cusps and closes the valves
State the function of atrioventricular valves.
AV valves are attached by a thin chordae tendinae to the papillary muscle that arises from the inner ventricular wall. When the ventricle contracts, papillary muscle also contracts and limits blood flow back into the atria
What causes the heart valves to open?
in order for valves to open up there must be a greater pressure in the atria which will cause the valve to open to the ventricle and the blood will automatically move
What is the bicuspid valve?
The left atrioventricular valve (also called the mitral valve)
What is the semilunar valve?
A three-cusped valve guarding the exit from one of the cardiac ventricles; the pulmonary and aortic valves
What is the sinoatrial (SA) node?
The SA node is the natural pacemaker of the heart; it is situated in the wall of the right atrium
What type of protein in our body is important for increasing the rate of reactions?
enzymes
What occurs when body ph is below average levels?
acidosis
What occurs when body ph is above average levels?
alkalosis
The cardiovascular system is divided into two circuits; what are they?
pulmonary; systemic
Describe the pulmonary circuit.
blood flows to and from the lungs; right ventricle is the pump
Describe the systemic circuit.
blood flows to and from the rest of the body; left ventricle is the pump
What is the ligamentum arteriosum?
the fibrous strand in adults that is the remnant of the ductus arteriosus of the fetal stage; stabilizes aortic arch to trunk
What are the four main chambers of the heart?
Right atrium, left atrium, right ventricle, left ventricle
What are the three sources of blood to the right atrium?
Coronary sinus, inferior vena cava, superior vena cava
What is the interventricular septum?
Portion of the heart that divides the right and left ventricle
What is the mediastinum?
the partition that is found in the middle of the thoracic cavity and on both sides of the mediastinum are the two lungs
Where does the apex of the heart point?
Towards the left hip
What do the papillary muscles attach to?
chordae tendinae
In relation to heart structure; is the fibrous pericardium superficial or deep?
superficial
What are the two layers of serous pericardium?
parietal; visceral
What is the parietal layer fused to?
parietal layer is directly attached (fused) to the interior surface of the fibrous pericardium
What is the space between the parietal layer and visceral layer?
pericardial cavity
What are hemopoietic stem cells?
stem cells whose division produce each of the various populations of blood cells
A needle being inserted into the heart would travel through the layers of the heart wall and covering in what order beginning with the outside
Fibrous pericardium, parietal pericardium, visceral pericardium, myocardium, endocardium
The atria are electrically isolated from the ventricles by what
The fibrous skeleton
The coronary sulcus is a grove on the outside of the heart that marks the division between what
Atria and ventricles
The frank starling law of the heart says that the higher the end diastolic volume, the…
Greater the stroke volume
Stimulation of the heart by parasympathetic nerve fibers cause
Decreased heart rate and no significant change in ventricular contractility
Which component of contractile cardiac muscle fibers prevents adjoining cells from pulling apart from one another
Desmosomes
Which statement is correct concerning pulmonary circulation
Oxygen poor blood returns from the body to the heart through the vena cava
The period lasting from closure of the AV valves to opening of the semilunar valves is called what
Isovolumic ventricular contraction
The chordae tendineae
Prevents the atrioventricular valve cusps from inverting into the atria during ventricular systole
A blood clot in the circumflex artery causes in myocardial infraction in part of the
Walls of the left atrium and posterior ventricular
Why is sustained or tetanic contraction of the heart impossible?
Because the refractory period in cardiac muscle lasts longer than the duration of the resultant contraction
Which of the following parts of the cardiac conduction system is correctly matched with this location
SA node- right atrium near the opening of the superior vena cava
While the atrium of the heart are in systole
Blood is being pumped into the ventricles
Small blood vessel‘s in tunica externa of a blood vessel that supply blood to the outer part of the vessel walls of a larger vessel are called
Vasa Vasorum
Erythropoietin is synthesized primarily by the
Kidneys
The major functions determining blood pressure are
Cardiac output and peripheral resistance
Resistance increases when
Length increases
Blood is moved through the vascular system by
The pressure gradient created by the heart
Baroreceptors are located in the
Walls of the aorta and carotid Arteries
Some capillaries contain these small opening in their endothelial called
Fenestrations
Which statement about precapillary sphincters is correct
They can close off the capillaries by contracting
As the total cross sectional area of the vascular tree_______, the velocity of flow_______
Increases, decreases
THe average blood volume for an adult is about
5 liters
Other than water, most common component of plasma is
Protein
For a person who is hematocrit is 45% in which choice below are the components of blood correctly ranked in order of decreasing percentage of total volume
Plasma, red blood cells, white blood cells
Once released from the bone marrow into the circulation the average lifespan of a red blood cell is about
4 months
Damage red blood cells are phagocytized by macrophages in the spleen or liver and their components are recycled EXCPET for
The heme group (minus the iron atom) which is converted into a green pigment called biliverdin
Myeloid Stem cells give rise to our blood cells except
Lymphocytes
The pacemaker of the heart is located in
SA node
An increase in Venous return most directly affects
Stroke volume
When normal arterial blood pressure decreases, baroreceptors cause a response that
Returns blood pressure back to normal
Jaundice is a buildup of ___________ in the circulation and interstitial spaces
Bilirubin
