Exam 1 Flashcards
1
Q
What is blood?
A
Aka “whole blood” it is the major connective tissue in the cardiovascular system. It is a fluid connective tissue.
2
Q
What are the functions of blood?
A
Transportation, protection, and regulation.
3
Q
What is the blood function of transportation?
A
Blood transports things around the body ie gasses, nutrition/wastes, chemical messengers (hormones), and cells (RBC, WBC, Platelets)
4
Q
What is the blood function of regulation?
A
Blood regulates temperature–made possible by its large percent composition of water, pH and ions–the pH range is 7.35-7.45 outside of which denatures proteins and cells, and tonicity–how the environment affects the cells shape which is important because a normal shape is vital for normal function.
5
Q
What is the composition of blood?
A
Plasma: 55%
Formed Elements: 45%
6
Q
What is the composition of formed elements?
A
Formed elements is another word for cells and cell parts containing 99% hematocrit–erythrocytes, and 1% Buffy Coat–leukocytes and platelets
7
Q
What is the composition of plasma?
A
92% Water
1% hormones, waste (CO2 & Urea), nutrients (some O2, glucose and other monomers (amino/fatty acids), and electrolytes (Na+, Ca2+, Cl+)
7% Proteins: 3 most common: Albumin, globulins, fibrinogen
8
Q
What is Albumin and what is its function?
A
Smallest, most abundant protein in blood plasma.
Functions to bind to hydrophobic compounds (lipids such as fatty acids and steroids) and prevents osmosis from plasma to tissues keeping water in the plasma, preventing tissue edema, and maintaining the osmotic pressure of blood.
9
Q
What are globulins and what do they do?
A
The medium-sized, medium-abundance protein in blood plasma
Alpha and Beta Globulins are transport globulins that bind to and transport lipid soluble vitamins, iron, and lipids
Gamma globulins are immunoglobulins aka antibodies that bind to pathogens.
10
Q
What are fibrinogens and what do they do?
A
The largest, least abundant blood plasma protein.
Functions to aid in blood clotting to keep RBC from leaking out of blood vessels
11
Q
What is the structure of erythrocytes?
A
Structure: biconcave (indented on top and bottom) allowing for flexibility (bending through bv), and maximization of surface area
12
Q
What are the components of erythrocytes?
A
Formed in red bone marrow, erythrocytes lack cell organelles and a nucleus which means that they cannot repair themselves leading to a lifespan of ~120 days (filtered out by spleen or liver)
Have Spectrin- special cytoskeleton protein to make it flexible
Has Hemoglobin (Hb) that fills the area empty from the lack of organelles and nucleus carrying about 250 million Hb molecules per cell
13
Q
What is the function and structure of hemoglobin?
A
Hb picks up O2 in th e lungs and releases it to the tissues in a reversible binding reaction
Four globin chains which are polypeptides– big chains of amino acids, that can bind reversibly to small percentages of CO2
Four Heme groups that contain a central Fe +2. This group is what binds reversibly to O2.
Each Hb can carry four O2
14
Q
What are the characteristics and structure of Leukocytes?
A
Leukocytes have the ability to move around and sometimes to leave the bv and crawl into a tissue this is called diapedesis
Structure: Have organelles and a nucleus, but have a short life span and is continually produced by red bone marrow
Leukocytes are either granular or agranular
15
Q
What is the difference between granular and agranular leukocytes and which leukocytes fall into these categories?
A
With or without visible speckles under the microscope (vesicles responding to dye)
Granulocytes: neutrophils, eosinophils, basophils
Agranulocytes: lymphocytes and monocytes
16
Q
What is the abundance, function, lifespan, granules and nuclei of a neutrophil?
A
Abundance: (most common) 50-70%
Function: Phagocytosis (mostly of bacteria) - they are the first responders at bacterial infection
Lifespan: 1-2 days
Granules: contain chemicals to kill bacteria (pyrogen that causes fever)
Nuclei: Multilobed- this is how you ID a neutrophil (cannot really see granules)
17
Q
What is the abundance, function, lifespan, granules and nuclei of an eosinophil?
A
Abundance: 1-4%
Function: Cytotoxic (dead cell) sometimes phagocytosis
Lifespan: 6-12 hours
Granules: Reddish granules releasing chemicals in response to parasites which is common in the digestive tract and to reduce inflammation by degrading histamine
Nuclei: Bilobed nuclei
18
Q
What is the abundance, function, lifespan, granules and nuclei of a basophil?
A
Abundance: <1%
Function: Inflammation makers
Lifespan: Unknown (1-2 days)
Granules: Release histamine (causes vasodilation to increase blood flow) & heparin (anticoagulant to increase blood flow)
-Responds to allergens and infection
-Moderates later stage inflammation
Nuclei: Hard to see nuclei behind big blue granules
Changes into Mast Cells when leaves blood
19
Q
What is the abundance, function, lifespan, and nuclei of a monocyte?
A
Abundance: 2-8%
Function: Large phagocytic cells
Lifespan: 8hrs in blood
Nuclei: Big & fat
Release chemicals to attract fibroblasts
Leaves blood called Macrophages (++ names)
20
Q
What do fibroblasts do?
A
Fibroblasts product collagen fibers to surround infected site
21
Q
What is the abundance, function, and nuclei of a lymphocyte?
A
Abundance: 20-40%
Function: Acquired immunity- which means that it facilitates responses to specific viruses- reexposure attack from memory.
- Responsible for response to antigens
Nuclei: Huge & round/oval
22
Q
What are the three types of lymphocytes and what do they do?
A
Natural Killer (NK) cells: attack cells that lack “self” proteins
T cells: attack foreign/diseased cells
B cells: secrete antibodies that bind to antigens
23
Q
What is the function and origin of platelets?
A
Function: in hemostasis (clotting process) to stop the bleed
Origin: Megakaryocyte Huge cells in red bone marrow
-Platelets form from fragments of membrane-enclosed packets of chemicals that flake off the apical surface of the Megakaryocyte
24
Q
What is hematopoises?
A
Hematopoiesis is the formation of all formed elements in bone marrow.
25
What is a hematopoietic stem cell?
A stem cell capable of becoming any formed element.
26
How does the body know to make Red blood cells?
The red bone marrow is notified by EPO--erythropoietin--a hormone released by the kidneys when they sense low blood oxygen levels.
27
What does the EPO cause?
The EPO causes hematopoietic stem cells in the red bone marrow to differentiate into pro-erythroblasts--a committed cell that can only turn into a RBC. This turns into an early stage erythroblasts which has lots of ribosomes to make protein (important because protein is a major component of Hb). This turns into late stage erythroblast that has a lot of Hb and ejects its nucleus as it differentiates into a reticulocyte which is released into circulation and its ribosomes breakdown. Once the ribosomes are broken down the cell is an erythrocyte.
28
Why is erythropoiesis homeostasis important and how is it maintained?
It is important because too many RBC makes blood too viscous.
It is maintained via negative feedback. Kidneys sense high oxygen in the blood and stop secreting EPO.
29
What nutrients are needed to make erythrocytes and what synthesis are they used for?
Iron: For Hb synthesis
Vitamin B12, Folic Acid: For DNA synthesis during erythropoiesis.
30
How can we get iron and how/where is it stored in the body?
Iron comes from our diet (meat, vegetables) or from recycles RBC
Iron is either being transported as T-Iron: bonded to the transport protein transferrin, as in the Spleen, small intestine, and plasma
or being stored as F-iron: bonded to ferritin, as in the liver.
31
What is the life cycle of a erythrocyte?
1) Low oxygen levels in the blood
2) EPO levels increase in the blood
3) RBC are made in the red bone marrow
4) RBC function in the blood stream for 120 days
5) Spleen filters out damaged RBC by macrophages
32
What happens to the erythrocyte in the spleen?
The Hb is broken into globin and heme
The globin is broken into amino acids which are released into the blood stream
The heme is broken into iron and bilirubin
33
What happens to the bilirubin once it has been released from the spleen?
Bilirubin is transported to the liver and is made into bile.
Bile is secreted into the small intestine for digestion
-some goes back to the liver via the circulatory system for reuse
-the rest stays in the digestive track and goes into the large intestine
From the large intestine the bile is either excreted as a specific bile byproduct "stercobilin" in the stool or is released into the blood stream as "urobilin" which is filtered out and excreted bia the kidneys giving urine its yellow color.
34
What happens to the iron once it is broken down in the spleen?
Iron leaves the spleen as T-iron.
the T-iron is mostly brought to the liver and stored as F-iron which will eventually be brought back to the red bone marrow and put into more red blood cells
34
What is hemostasis? What are the three steps?
All the processes which prevent bleeding when a blood vessel is damages
1) Vasoconstriction: "vascular spasm"
2) Platelet plug: not keep all RBC in but better than nothing
3) Clot formation: stronger more stable structure in place until repair
35
What happens in vascular spasm?
Damages blood vessel constricts decreasing the lumen so less blood can flow and less can escape triggered by chemical released by damaged endothelium this is the automatic constriction of smooth muscles
It is sustained by chemical released by platelets
36
What is endothelium?
Endothelium is the epithelial cells lining blood vessels
37
What begins the platelet plug?
Many substances flow in the plasma while remaining inactivated such as von Willebrand factors and coagulation factors. vWf is activated when exposed to collagen which only occurs in a damaged blood vessel
38
What is directly below the endothelium in blood vessels?
Connective tissue called subendothelium which is mostly made of collagen fibers
39
What happens to form the platelet plug once vWF are activated?
Platelets bind to "stick" to activated vWF then platelets aggregate (clump) and platelets release secretions making them more sticky via a positive feedback loop.
40
What are the platelet secretions?
Platelets contains chemicals even though they do not have organelles.
Platelets secrete serotonin, ADP, Thromboxane A2 (TXA2) and Ca +2
41
What does serotonin do?
Serotonin causes vasoconstriction to maintain vessel constriction
42
What does ADP do?
ADP increased platelet aggregation, enlarge platelets, change platelet shape, and cause platelets to become more sticky. ADP is involved in the positive feedback loop.
43
What does thromboxane A2 do?
Thromboxane A2 causes vasoconstriction and increases platelet aggregation (which is a positive feedback loop)
44
What does Ca+2 do?
Ca 2+ is not a part of plug formation but in the coagulation cascade that forms the blood clot.
45
What is the last step of the platelet plug formation?
Platelets contract the size of the platelet plug by activating the actin and myosin in them.
46
What prevents platelet plugs from occurring or from getting too large?
Secretions from healthy endothelium cells: Prostacyclin (PGl2) and Nitric oxide (NO) prevent platelet secretions.
Platelet plug grows until it reaches an area high in these secretions.
47
What is the use of the Fibrin clot formation?
This is the long term fix to keep RBCs from leaking out.
48
What are the two pathways of fibrin clot formation and what do they do?
Intrinsic pathway: factors arising from inside the blood vessel- major factor being Factor XII that is always present in the plasma and is activated by contact with the subendothelium.
Extrinsic pathway: factors arising from damaged tissue outside the blood vessel. Major factor being Tissue Factor (released by damaged tissue outside the blood vessel)
Sese kick off the clot, they activate the coagulation cascade
*these factors typically are simultaneously active*
49
What is the coagulation cascade?
A I/E pathway activates factor X (X Xa). Xa reacts with Factor V, Ca +2, and Phospholipids on platelets and converts prothrombin to thrombin
50
What does thrombin do?
Activates Factor X and Factors in intrinsic pathway (a positive feedback loop: the more thrombin you have the more thrombin you have). Causes an increase in platelet aggregation so they continue to aggregate even while clot is forming. Converts fibrinogen (plasma protein) to fibrin (more cohesive network for cot formation)and converts XIII to XIIIa
51
What does thrombin do?
Activates Factor X and Factors in intrinsic pathway (a positive feedback loop: the more thrombin you have the more thrombin you have). Causes an increase in platelet aggregation so they continue to aggregate even while clot is forming. Converts fibrinogen (plasma protein) to fibrin (more cohesive network of proteins for clot formation) and converts XIII to XIIIa
52
What are the other minor factors in the coagulation cascade?
Factor VII, VIII, IX & XI
53
What limits clot formation and breaks down clots?
Anticoagulants and Fibrinolysis
54
What are anticoagulants?
produced by healthy endothelium, Heparin and Anti-thrombin III (which limits thrombin production) block active factors in the coagulation cascade
55
What is fibrinolysis?
This is a form of clot breakdown what uses chemicals called tissue plasminogen activator (tPA) & Thrombin. These two chemicals convert plasminogen to plasmin which is an enzyme that will dissolve the clot by breaking fibrin down into fibrin fragments
56
What are three clot disorders?
Hemophilia, von Willebrand's Disease, and Vitamin K deficiency.
57
What is hemophilia?
Hemophilia is a genetic condition that interferes with clot formation often by interfering with Factor VIII formation in the liver. This leads to no coagulation cascade
58
What is von Willebrand's disease?
This is when there is not enough von Willebrand Factors in the plasma which interferes with platelet plug formation.
59
What does Vitamin K deficiency cause?
This deficiency causes coagulation factors to not be made in the liver which leads to no coagulation cascade.
60
What is the location and orientation of the heart?
The heart is within the pericardial cavity which is within the mediastinum which is within the thoracic cavity. The heart is almost directly deep to the sternum (in the center of the chest), but its apex is towards the left side slightly decreasing the size of the left lung.
61
What is the pericardial sac and what is its composition?
This is the actual structure housed within the pericardial cavity. It is made of a fibrous outer layer and a serous membrane inner lining.
62
What is the fibrous outer layer of the pericardial sac?
It is made of dense connective tissue and secures the heart to the diaphragm below and the major blood vessels above keeping the heart in place and preventing it from over filling
63
What is the serous membrane inner lining of the pericardial sac?
It is the parietal layer of the serous membrane adhering to the fibrous pericardium and secreting serous fluid to prevent abrasions.
64
What layer is deep to the serous membrane inner lining of the pericardial sac?
The epicardium which is the visceral layer of the serous membrane also called the visceral pericardium that adheres to the surface of the heart.
65
What are the layers surrounding the heart superficial to deep?
Fibrous pericardium, parietal layer of serous pericardium, pericardial cavity (filled with serous fluid), epicardium, myocardium, and endocardium.
66
What kind of heart do humans have and what advantage does this give?
Humans have a double-pump, that is, a four-chambered heart that allows for the effective separation of oxygenated and deoxygenated blood.
67
What are the two circuits of the heart?
Pulmonary circuit: Blood between heart and lungs. Right to left chamber
Systemic circuit: Blood between heart and rest of body left to right chamber.
68
What is the role of the right atrium and what structures are contained within it?
Receives deoxygenated blood from the systemic circuit through the superior/inferior vena cava, and coronary sinus.
Contains the fossa ovalis which is the remnant (closed hole) of the foramen ovale which was a hole between the atria during baby development in the womb
Tricuspid valve: right atrioventricular one-way valve
69
What is the role of the right ventricle and what are the structures contained within it?
Receives deoxygenated blood from the right atrium through the tricuspid valve.
Contains: Chordae tendonae that attaches to tricuspid and capillary muscle to ensure valve only opens into the RV. Trabeculae carneae: "meat branches" bumps of muscle scene due to the larger layer of myocardium in the ventricles than the atria
Pulmonary semilunar valve: one way valve to the pulmonary trunk and pulmonary arteries in the pulmonary circuit
70
What is the role of the left atrium and what is contained in it that is not contained in the right atrium?
Receives oxygenated blood from the pulmonary circuit through the right and left pulmonary veins (4 total). Bicuspid (Mitral) valve: left atrioventricular valve
71
What is the function of the left ventricle and what is different from the right ventricle?
Receives oxygenated blood from the left atrium through the bicuspid valve.
Left has a thicker myocardium because it must pump blood to the whole body. Interventricular septum separates R&L ventricles has electricity-conducting fibers
Aortic semilunar valve leads to ascending aorta and coronary arteries (heart gets 1st dibs on blood) and systemic circulation
72
What is the cardiac skeleton and what is its function?
Dense connective tissue that surrounds all four valves
Functions to anchor the valve cusps so that they stay in one place, prevent over-dilation of valve openings, main point of insertion for cardiac muscle- for cardiac muscle bundles allows blood to be squeezed out, and blocks the direct spread of electrical impulses.
73
Why must the cardiac skeleton block the direct spread of electrical impulses?
Because unlike a skeletal muscle that moves as a motor unit, cardiac muscle only has two or three points that connect it to the nervous system. Most impulses pass between cells through gap junctions. To allow only one area of the heart to contract the impulse must be physically stopped between the cells.
74
What two structures coordinate cardiac contractions?
Myogenic cells and conducting fibers
75
What are myogenic cells and what are the two types?
Myogenic cells are cells in the heart capable of producing contractions in the heart muscle by creating an electrical signal. these are autorhythmic cells two examples being sinoatrial node and the atrioventricular node
76
What is the location and function of the sinoatrial node?
Location: top of right atria
Function: Contracts both atria
-establishes the rate of contraction (how fast the heart is beating
77
What is the location and function of the atrioventricular node?
Between the right atria and ventricle.
Function: Receives signal from the SA node, pauses (~0.1 sec), then sends signal (propagates the depolarization to the ventricle)
78
Why does the AV node pause?
To separate the SA & AV so that the atria contracts before the ventricle
79
What are the conducting fibers and what are their function?
AV bundle (Bundle of His), Right and left bundle branches, and the purkinje fibers.
Function: carry depolarization signal (the big positive charge in muscle cells) quickly from AV to septum to myocardium where they cause the ventricles to contract
80
What are the two aspects of an ECG?
Three major waves and three segments of
81
What are the three major waves of an ECG?
P: Atrial depolarization (contraction) [SA--> AV]
QRS: Wave ventricular depolarization and atrial repolarization [AV-->Perkinje]
T: Ventricular repolarization
82
What are the segments of an ECG?
P-R: Beginning of P to beginning of Q time takes for signal to go from the AV to the AV bundle
S-T: End of S to beginning of T Time takes for ventricles to depolarize
Q-T: Beginning of Q - end of T times for entire ventricle depolarization-repolarization
83
What does the mechanical activity of the heart depend on?
The heart acting as a pump to create pressure changes in the heart to move blood through the heart and vessels.
84
What is diastole and systole and what do these mean for the heart?
Diastole: low pressure
Systole: high pressure
These two are used for blood pressure and for pressure in the heart at any point
85
What are the five stages of the heart cycle?
1) Late diastole
2) Atrial systole
3) Isovolumic Ventricular Contraction
4) Ventricular Ejection
5) Isovolumic Ventricular Relaxation
86
What happens in the late diastole stage of the heart cycle?
This is ventricular diastole
All chambers are relaxed and ventricles fill passively, that is, blood is filling along the pressure gradient (high to low). The chambers are low pressure and the vessels are high pressure
87
What happens in the late diastole stage of the heart cycle?
This is ventricular diastole
All chambers are relaxed and ventricles fill passively, that is, blood is filling along the pressure gradient (high to low). The chambers are low pressure and the vessels are high pressure
AV valves are open and semilunar valves are closed
88
What happens during the atrial systole stage of the heart cycle?
High pressure in the atria because the atria are contracting. The ventricles are topped off with blood because they are an area of low pressure. The valves stay the same (AV open, semilunar shut)
89
What happens during the isovolumic Ventricular contraction?
This is the first phase of ventricular contraction. Pressure builds to push the AV valves closed but not enough pressure to open semilunar valves. "same volume in ventricles"." Close of AV valves cause "lub" sound: first heart sound. This is the end diastolic volume: the maximum volume in the ventricles
90
What happens in the ventricular ejection phase of the heart cycle?
The pressure on the ventricle builds to exceed the pressure in the arteries forcing the semilunar valves open and ejecting the blood into the pulmonary trunk and ascending aorta until ventricles are empty and they relax.
91
What happens during the Isovolumic Ventricular Relaxation?
Ventricles relax and their pressure falls. Blood flows back into cusps of semilunar valves and snaps them closed causing the second heart sound: dup. All the valves are now closed. This is the End Systolic Volume (ESV)
92
What is the Wiggers Diagram?
It is a diagram of the heart cycle that tracks the changes in blood pressure in the heart and aorta.
Understand how the pressure changes due to what is going on with the chambers of the heart and how blood is allowed to flow due to the valves.
93
What is stroke volume and what is the formula?
Stroke volume is the amount of blood pumped by one ventricle contraction. EDV-ESV = stroke volume
94
What is the Frank-Starling Law?
Increased stretch of the heart leads to increased contractile force
95
What can increase contractile force?
Stretch of ventricles caused by amount of blood putting stress on the ventricle
Presence of inotropic agents such as norepinephrine and epinephrine
Increased stretch by increased rate of venous return that could be caused by constricted vessels
96
What is cardiac output and what is the formula?
The amount of blood pumped by the heart per minute
Heart Rate X Stroke Volume = Cardiac Output
97
What aspect of the nervous system effects the heart?
Peripheral, autonomic both parasympathetic and sympathetic.
98
What **structures** of the parasympathetic nervous system affect the heart?
Cardioinhibitory area of the medula;
Pre-ganglionic neurons with axons in the vagus nerve contact post-ganglionic neurons in terminal ganglia.
Post-ganglions neurons secrete ACh on SA & AV nodes
99
**How** does the parasympathetic nervous system affect the heart?
The parasympathetic nervous system lowers the heart rate set by the SA node of 90 bpm to 70 bpm by secreting ACh, adding negative charge, hyperpolarizing the SA & AV nodes causing them to take longer to depolarize making both function slower
100
What **structures** of the sympathetic nervous system affect the heart?
The cardioexcitatory area of the medulla
Pre-ganglionic neurons in the spinal cord contact post-ganglionic neurons in the sympathetic chain ganglia
Post-ganglionic neurons secrete norepinephrine on the SA, AV, & ventricular myocardium
101
**How** does the sympathetic nervous system affect the heart?
With the NE of the sympathetic nervous system the SA node sets a heart rate greater than 90 bpm.
Adding positive charge the SA node is depolarized making it reach its threshold easier.
Increased heart rate is mostly due to the effect on the SA but also on the AV.
The stimulation of the ventricular myocardium increases contractile force causing more blood to leave the heart.
102
What are the three layers of blood vessels?
Tunica intima: endothelium made of epithelium that lines the lumen (open space) creating a smooth surface for blood flow and releasing chemicals that moderate clot formation
Tunica Media: Made of smooth muscle for vasoconstriction/dilation controlling the blood flow through the vessel
Tunica Externa: Connective (fibrous) tissue, anchors blood vessels in place
103
What is an artery and where are the three types found?
Blood vessels that carry blood AWAY from the heart
Elastic arteries: closest to heart
Muscular arteries:
Arterioles: Farthest from heart
104
What are the characteristics of elastic arteries?
Large diameter, **highest** blood pressure,
T. Intima: endothelium elastic fibers in membrane,
T. Media: Thick smooth muscle layer, elastic fibers surrounding the muscle cells, vasa vasorum (vessels in vessels)
T. Externa: Collagen fibers, some muscle in larger vessels, vasa vasorium
105
What are the characteristics of muscular arteries?
Medium diameter, high blood pressure,
T. Intima: endothelium with elastic membrane supporting it,
T. Media: thick muscle layer, few elastic fibers
T. Externa: Collagen fibers, vasa vasorum
*they don't **always** carry oxygenated blood*
106
What are the characteristics of arterioles?
Small diameter, moderate pressure
T. Intima: Endothelium **no** elastic fibers.
T. Media: Thick muscle layer compared to size of vessel
T. Externa: Thin layer of collagen fibers
107
What is the necessary characteristics of the blood vessels that allow for the exchange of materials?
A thin layer of cells in the blood vessel wall
108
What are capillaries and what are their general characteristics and what are the names of the three types and what do their distinctions depend on?
Capillaries allow for the diffusion of materials between tissues and blood vessels because they have only one layer
Smallest diameter (about one RBC wide), lowest **velocity**, low pressure *but not the lowest*
T Intima: Endothelium, no T Media or Externa
Continuous, fenestrated, sinusoid depending on what you want to let out
109
What are the aspects of a continuous capillary?
Most common capillaries
Some junctions between cells
Materials must get through to blood vessel itself between the cells
Materials: little molecules- nutrients, gases, hormones, leukocytes
110
What are the aspects of a fenestrated capillary?
More rare than continuous
Have little "windows" that allow larger molecules to pass through
Located in intestines, kidneys, brain
Materials: Larger molecules- proteins, carbohydrates
111
What are the aspects of a sinusoid capillary?
"Sinus" = very wide spaces
These capillaries have very large paces in their endothelium. These large cellular gaps are caused by an incomplete basement membrane and fenestrations
Located: Liver, spleen, red bone marrow, endocrine glands
Materials: Large molecules- blood cells, large nutrients
112
What are the characteristics of venules?
Larger lumen than arteriole of same size, small vessel diameter
**Lowest** pressure in the body
T Intima: endothelium
T Media: thinnest muscle layer to no muscle
T. Externa: collagen fibers
113
What are the characteristics of veins?
**lowest** pressure so need one-way valves keeping the blood going towards the heart
larger lumen than similarly sized arteries
T. Intima: endothelium, T. Media: thin muscle layers, T. Externa: collagen fibers, thickest layer, small amount of elastic tissue & in largest veins: vasa vasorum
114
What are the three ways blood in veins can return to the heart?
1) Skeletal pump: muscles contact pushing on veins giving them pressure
2) Respiratory Pump: breathe causes pressure change in thoracic cavity & abdomen which pushes on veins in the abdomen and chest
3) Vasoconstriction of veins: sympathetic innervation of blood vessels causes constriction of thin larger muscles
115
What is the relationship between pressure and flow in body vessels?
Fluids & gases flow down the pressure gradient (high to low)
116
What produces the high pressure in the artieries
The heart
117
What is resistance, what three things affect it, and what is its relationship to flow?
Resistance is the opposition of flow. Flow is inversely proportional to resistance.
-Resistance proportional to length of tube: R increase, L increase
-Resistance is proportional to viscosity (thickness): R increase, V increase
-Resistance is inversely proportional to diameter: R decrease D increase
118
What is the stimulus, receptor/sensor, integration/control center, output, target(s), and response(s) of vasopressin?
Stimulus:
1) high osmolarity
2) decreased BP
3) decreased atrial stretch
Receptor/sensor:
1) Osmoreceptors in hypothalamus
2) Baroreceptors in carotid artery and aorta
3) Stretch receptors in the heart
Integration:
Hypothalamus
Output:
Vasopressin (made in hypothalamus released from posterior pituitary)
Targets:
Collecting ducts of kidneys (to express more water leak channels)
Responses:
More water absorbed out of filtrate (becomes urine) to blood, BP increased (b/c increased volume)
119
What is the stimulus, receptor/sensor, integration/control center, output, target(s), and response(s) of aldosterone?
Stimulus:
hyperkalemia ( excess K+)
Decreased blood pressure
Receptor: Adrenal Cortex
Integrator: Adrenal Cortex
Output: Aldosterone
Targets: Collecting ducts of the kidneys
Response:
Increased Na+ reabsorption increasing blood volumes
K+ secretion
Increased blood pressure
120
What is the stimulus, receptor/sensor, integration/control center, output, target(s), and response(s) of Atrial natriuretic hormone?
Stimulus:
Increased blood pressure
increased atrial stretch
Receptor: Myocardium of heart
Integration: Myocardium of heart
Output: Atrial natriuretic hormone
Targets/responses: Decreased BP
1) hypothalamus/decreased vasopressin release, increased NaCl & H2O secretions, decreasing blood volume
2) Kidneys/Secrete less renin
3) Adrenal Gland/ decreased Na+ absorption, increased NaCl & H2O secretion, decreased blood volume
4) Medulla/decreased sympathetic output
121
What is the stimulus, receptor/sensor, integration/control center, output, target(s), and response(s) of Renin?
Stimulus:
1) Decreased BP
2) Decreased Glomerulus Filtration Rate
Receptor:
1) Granular cells of the kidneys
1) Cardiovascular control center of the medulla oblongata
2) Macula Densa Cells
Integration: Granular cells of the kidneys
Output: Renin
interacts with angiotensinogen --> angiotensin I. ANG I+ ACE (Angiotensin Converting Enzyme) = Angiotensin II.
Targets/Response: (targeted by ANG II to increase (i) BP)
1) Arterioles/Vasoconstriction, i BP
2) Cardiovascular control center of medulla oblongata/ i cardiovascular response, i BP
3) Hypothalamus/ i vasopressin and thirst, i blood vol and maintain osmolarity, i BP
4)Adrenal Cortex: i aldosterone secretion, i Na+ absorption, i vol & maintain osmolarity, i BP
5) Proximal tubule of nephron/ i Na+ reabsorption, i vol & maintain osmolarity. i BP
122
What role does arterial pressure play in blood pressure?
The elastic arteries expand with the **high** blood pressure from ventricle contraction creating the systolic blood pressure (~120mmHg) and then recoil to push the blood into circulation while the ventricle relaxes creating the diastolic blood pressure (<80mmHg)
123
What is the equation for pulse pressure?
Systolic BP - Diastolic BP = Pulse Pressure
124
What is the equation for Mean Arterial Pressure and why is it different from pulse pressure?
Diastolic + 1/3 Pulse Pressure = MAP
We add another diastolic because the heart spends more time in diastole.
125
What structure carries the depolarization signal into the myocardium of the ventricles?
Purkinjie fivbers
126
What structure carries the depolarization signal into the myocardium of the ventricles?
Purkinje fibers
127
How do the ventricles contract and why?
From the apex to the base so that the heart can push blood into the pulmonary trunk and aorta at the top of each ventricle.
128
What happens to the fibrin?
Reacts with activated Factor XIII to form a stable mesh network of fibrin which then traps erythrocytes to form the fibrin clot
