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MCAT Biology Review 2025-26 > Chapter 7: The Cadiovascular System > Flashcards

Chapter 7: The Cadiovascular System Flashcards

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1
Q

The cardiovascular system

A

Consist of a four chambered heart, blood vessels, and blood.

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2
Q

Veins

A

Return deoxygenated blood to the heart, except for the pulmonary vein which takes oxygenated blood to the heart.

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3
Q

Superior vena cava

A

Carries deoxygenated blood from the systemic circuit of the head neck and arms to the right atrium.

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4
Q

Inferior vena cava

A

Returns deoxygenated blood from the systemic circuit of the internal organs and legs to the right atrium.

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5
Q

Right atrium

A

Accepts deoxygenated blood from the superior vena cava and the inferior vena cava and pumps the deoxygenated blood through the tricuspid valve to the right ventricle.

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6
Q

Right ventricle

A

Pumps deoxygenated blood into the pulmonary arteries through the pulmonary semilunar valve and into the pulmonary circuit of the lungs.

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7
Q

Left atrium

A

Accepts oxygenated blood from the pulmonary circuits via the pulmonary veins and pumps oxygenated blood through the mitral (bicupsid) valve into the left ventricle.

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8
Q

Left ventricle

A

Pumps oxygenated blood into the systemic circuit. Pumps oxygenated blood through aortic semilunar valve the into both the head, neck, and arms systemic circuit (via the aorta) and the internal organ and leg systemic circuit (via the descending aorta).

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9
Q

Descending aorta

A

Artery that brings oxygenated blood from the left ventricle into the internal organ and legs systemic circuit.

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10
Q

Aorta

A

Artery that carries oxygenated blood from the left ventricle to the head, neck, and arms systemic circuit.

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11
Q

Pulmonary vein

A

Carries oxygenated blood from the pulmonary circuit to the left atrium.

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12
Q

Tricuspid valve

A

One-way valve that separates the right atrium and the right ventricle.

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13
Q

Bicuspid valve

A

One-way valve separates the left atrium and left ventricle.

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14
Q

The right side of the heart

A

Accepts deoxygenated blood from the inferior and superior vena cavae returning from the somatic circulation into the right atrium, moving through the tricuspid valve into the right ventricle, past the pulmonary semilunar valve and into the pulmonary circuit by way of the pulmonary arteries.

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15
Q

Pulmonary circulation

A

The right side of the heart accepts deoxygenated blood returning from the body and moves it to the lungs by way of the pulmonary arteries.

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16
Q

Left side of the heart

A

Receives oxygenated blood from the pulmonary circuit by way of the pulmonary veins into the left atrium, past the mitral valve and into the left ventricle, through the aortic valve and forces it out to the body through the aorta and the descending aorta into the systemic circuit.

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17
Q

Systemic circulation

A

The left side of the heart receives oxygenated blood from the lungs by the pulmonary veins and forces it out to the body through the aorta into the head, neck, and brain; and through the descending aorta into the legs and organs.

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18
Q

LAB RAT mnemonic

A

Left Atrium = Bicupsid
Right Atrium = Tricupsid

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19
Q

Atria

A

Thin walled structures of the heart where blood is received either by the venae cavae (deoxygenated blood entering the right side of the heart) or the pulmonary veins (oxygenated blood entering the left side of the heart)

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20
Q

What are the ventricles?

A

Thick walled structures of the heart that contract to send blood to the lungs (right ventricle) and this systemic circulation (left ventricle)

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21
Q

Atrioventricular valves

A

Bicupsid or mitral valve (left atrium to left ventricle)

Tricuspid (right atrium to right ventricle)

Separate the atrium and ventricle.

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22
Q

Semilunar valves

A

Pulmonary valve (right) and aortic valve (left)

Separate the ventricle from the vascular.

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23
Q

Pulmonary valve

A

One of the semilunar valves in the heart. Separates the right ventricle from the pulmonary circuit.

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24
Q

Aortic valve

A

One of the lunar valves in the heart. Separates the left ventricle from the aorta.

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25
Q

Electrical impulse pathway in order of excitation

A

Sinoatrial node (SA)
Atrioventricular node (AV)
The bundle of His (AV bundle)
The Purkinje (per-kin-yay) fibers.

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26
Q

Sinoatrial node (SA node)

A

Node where impulse initiation occurs. Does not require any neurological input. Causes the two atria to contract simultaneously. Located above the right atrium.

Whereas most ventricular filling is passive (that is blood moves from the atria to the ventricles based on ventricular relaxation) Atrial systole (contraction) results in an increase in atrial pressure that forces a little more blood into the ventricles.

Remember: SA node-AV node-bundle of His-Purkinje fibers

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27
Q

Systole

A

Contraction

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28
Q

Atrial kick

A

Additional volume of blood injected into the ventricles, accounts for about 5 to 30% of cardiac output, caused by the atrial systole, impulsed by the sinoatrial (SA) node.

Note: most of the blood that makes it into the ventricles gets there by the ventricle relaxing.

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29
Q

Atrioventricular (AV) node

A

Sits at the junction of the atria and ventricles. Signal is delayed so that the ventricles can fill completely before contraction.

Remember: SA node-AV node-bundle of His-Purkinje (per-kin-yay) fibers

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30
Q

Bundle of His (AV bundle)

A

Embedded in the interventricular septum (wall). Receives signal from the atrioventricular (AV) node.

Remember: SA node-AV node-bundle of His-Purkinje (per-kin-yay) fibers

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31
Q

Purkinje (per-kin-yay) fibers

A

Distribute electrical signals through the ventricular muscle. Receives signal from the bundle of His (AV bundle).

Remember: Sinoatrial (SA) node, Atrioventricular (AV) node, bundle of His (AV bundle), Perkinje (per-kin-yay) fibers.

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32
Q

Intrinsic rhythm of the sinoatrial (SA) node

A

60 to 100 signals per minute.

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33
Q

Myogenic activity

A

Myogenic activity refers to the ability of the cardiac muscle to contract with without any neurological input. Even if all innervation to the heart is cut, the SA node will still initiate impulse. The neurological input to the heart is important in speeding up and slowing the rate of contraction, but not generating it in the first place.

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34
Q

EKG or ECG

A

Electrocardiogram. Detecting the hearts electrical impulses by placing electrodes on the skin on opposite sides of the heart. Assess the status of a patient’s heart. Electrical spikes of the EKG occurred just before a cardiac contractile event because depolarization proceeds cardiac muscle contraction.

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35
Q

Autonomic control of the circulatory system

A

The autonomic system consists of the sympathetic (fight or flight) and parasympathetic (rest and digest) branches. Sympathetic signal speed up the heart rate and increase to contractility of cardiac muscle, well parasympathetic signal slow down the heart rate.

Remember from chapter 4: the vagus nerve provides the signal to slow down the heart rate from the parasympathetic signals.

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36
Q

Two phases of heart contraction

A

Systole and diastole

Systole: ventricles contact and pump blood into arteries.

Diastole: heart relaxes and fills with blood.

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37
Q

Systole contraction

A

Ventricular contraction and closure of the AV valves, blood is pumped out of the ventricles. Systole contraction is a higher pressure than diastole contraction.

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38
Q

Diastole contraction

A

The ventricles are relaxed, the semi lunar valves are closed, and blood from the atria fill the ventricles. Diastole contraction is a lower pressure than systole contraction.

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39
Q

Cardiac output

A

Total blood volume pumped by ventricle in one minute. Cardiac output is approximately 5 liters per minute.

CO = HR x SV

Cardiac output is the product of the heart rate and stroke volume.

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40
Q

Heart rate

A

Beats per minute

CO = HR x SV

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41
Q

Stroke volume

A

Volume of blood pumped per beat

CO = HR x SV

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42
Q

Relationship of cardiac output, heart rate, and stroke volume

A

Since the two pumps are connected in series, the volume of blood passing through each side must be the same.

Cardiac output is the product of heart rate and stroke volume.

CO = HR x SV

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43
Q

Rhythmic impulses of the heart

A
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44
Q

The cardiac cycle graph

A
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45
Q

Tunic as a medical term

A

an enveloping membrane or layer of body tissue.

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46
Q

Three major types of blood vessels

A

Arteries, veins, and capillaries

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47
Q

Arteries

A

Blood travels away from the heart in arteries.

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48
Q

Arterioles

A

Arteries undergo further division and name changes as they divert blood to specific tissues and organs, and upon reaching their target are known as arterioles.

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49
Q

Capillaries

A

Further branching of arterioles. Capillaries perfuse the target tissue.

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50
Q

Endothelial cells

A

Special type of cell lining in all blood vessels that help maintain the vessel by releasing chemicals that aid in vasodilation and vasoconstriction. allow white blood cells to pass through the vessel wall and into the tissues during an inflammatory response. Release certain chemicals when damage that are involved in the formation of blood clots to repair the vessel and stop bleeding.

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51
Q

Main structural difference between veins and arteries

A

Arteries have much more smooth muscles than veins. The smooth muscle in arteries provides elasticity that maintains blood pressure.

Interesting: without the elasticity of arteries, blood pressure would effectively drop to zero.

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52
Q

Two kinds of arteries that contain deoxygenated blood

A

Pulmonary arteries
Umbilical arteries

All other arteries contain oxygenated blood.

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53
Q

Capillaries

A

Vessels with a single endothelial layer. The thin wall of the capillary allows easy diffusion of gases (O2 and CO2), nutrients (glucose), wastes (urea and ammonia), and hormones. Capillaries allow endocrine signals to arrive at their target tissue.

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54
Q

Only two kinds of veins that carry oxygenated blood

A

Pulmonary vein
Umbilical vein

All other veins carry deoxygenated blood.

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55
Q

Venules

A

Smaller Venus structures that connect capillaries to the larger veins of the body.

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56
Q

Blood flow through the heart

A
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57
Q

Portal systems

A

Systems in which blood will pass through two capillary beds in series before returning to the heart.

There are three. The hepatic, renal, and hypophyseal portal systems.

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58
Q

The three portal systems in the body

A

Hepatic portal system
Hypophyseal portal system
Renal portal system

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59
Q

Hepatic portal system

A

Blood leaving the capillary beds in the walls of the gut passes through the hepatic portal vein before reaching the capillary beds in the liver

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60
Q

Hypophyseal portal system

A

Capillary beds in the hypothalamus travel to a capillary bed in the anterior pituitary to allow peregrine secretion of releasing hormones.

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61
Q

Renal portal system

A

Blood leaving the glomerulus travels through an EFFERENT ARTERIAL (which is specific to urinary system) before surrounding the nephron in a capillary network called the vasa recta.

62
Q

Glomerulus

A

Network of capillaries in the kidneys.

A cluster of nerve endings, spores, or small blood vessels, in particular a cluster of capillaries around the end of a kidney tubule, where waste products are filtered from the blood.

63
Q

Nephron

A

The functional units of the kidney that filter blood, regulate blood pressure and volume, and remove waste from the body.

64
Q

Vasa recta

A

A group of blood vessels in the kidney and intestines that supply oxygen and nutrients, and play a role in urine concentration. The vasa recta are a series of hairpin-shaped blood vessels that supply the kidney’s medulla with oxygen and nutrients.

65
Q

Blood composition by volume

A

55% liquid
45% cells

66
Q

Blood plasma

A

The liquid portion of blood, an aqueous mixture of nutrients, salts, respiratory gases, hormones, and blood proteins.

67
Q

Blood serum

A

Refined plasma, made by removal of clotting factors.

68
Q

The three cellular categories of blood.

A

Erythrocytes
Leukocytes
Platelets (thrombocytes)

69
Q

Where are all blood cells formed?

A

All blood cells are formed from hematopoietic stem cells, which originate in the bone marrow.

Remember: poietic means of or relating to making or forming.

70
Q

Erythrocytes

A

Red blood cells. Specialized cell containing hemoglobin designed for oxygen transport. Mature red blood cells contain no nuclei, mitochondria, or other membrane bound organelles. Given that they have no mitochondria, the erythrocyte does not consume the oxygen it is carrying before it is delivered to the peripheral tissues. In other words, red blood cells do not carry out oxidative phosphorylation to generate ATP, but rather use GLYCOLYSIS with lactic acid (arising from fermentation) as the main byproduct. They have no nucleus therefore they are unable to divide. Can live for 120 days in the bloodstream before cells in the liver and spleen phagocytize senescent (old) red blood cells to recycle them for their parts.

Remember: oxygen is nonpolar and therefore has low solubility and aqueous environments.

71
Q

Organs in the body that process waste

A

Lungs, liver, and kidneys

72
Q

Two commonly given measures of red blood cells in blood count

A

Hemoglobin and hematocrit.

Hematocrit is the percentage by volume of red blood cells in your blood. 40-50% in men, 35-45% in women, 30-45% in children.

Hemoglobin is a protein in blood that carries oxygen to tissues. Hemoglobin is measured in grams/decileter. Norman is around 15-17 for men and 12-15 for women.

73
Q

Hematocrit

A

Measure of how much of a blood sample consist of red blood cells, given as a percentage.

74
Q

Normal range of hemoglobin and hematocrit in a blood count for males and females

A

13.5 — 17.5 g/dL hemoglobin, 41-53% hematocrit for males.

12.0 — 16.0 g/dL hemoglobin, 36-46% hematocrit for females.

75
Q

Leukocytes

A

White blood cells. Comprise less than 1% of total blood volume. Acts as defenders against pathogens, foreign cells, cancer, and other materials not recognized as self.

76
Q

Two classes of leukocytes

A

Granulocytes (neutrophils, eosinophils, and basophils)

Agranulocytes (Lymphocytes, monocytes)

77
Q

-phil suffix in medicine

A

Lover of
Having an affinity for
Enthusiast of

Comes from the Greek word philos, which means “dear beloved”

78
Q

Three types of granular leukocytes

A

Neutrophils
Eosinophils
Basophils

79
Q

Two types of agranulocytes

A

Lymphocytes
Monocytes

80
Q

Granular leukocytes

A

Contain cytoplasmic granules that are visible by microscopy. These cytoplasmic granules contain a variety of compounds that are toxic to invading microbes, these granular compounds can be released through exocytosis. Involved in inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites.

81
Q

Agranulocytes

A

Do not contain granules that are released by exocytosis. Lymphocytes and monocytes.

82
Q

Lymphocytes

A

Act as primary responders against an infection, function to maintain a long-term memory bank of pathogen recognition. Help our body learn from experience and prepared to mount a fast response upon repeated exposure to familiar pathogens.

83
Q

Specific immune response

A

The body’s targeted fight against particular pathogens, such as viruses and bacteria

Specific, think targeted.

84
Q

Antigenic protein

A

An antigen is any specific target, usually a protein, to which the immune system can act.

85
Q

Vaccines and lymphocytes

A

Many vaccines work by training lymphocytes. Through exposure of a weakened pathogen or an antigenic protein of the pathogen, memory cells can be created.

86
Q

Three types of lymphocytes

A

B - cells
T – cells
Natural killer cells

87
Q

B - cell

A

White blood cells, mature lymphocytes (agranulocytes), responsible for antibody generation. Mature in the bone marrow.

88
Q

T-cell

A

White blood cells, mature lymphocytes (agranulocytes), that kill virally infected cells and activate other immune cells. Mature in the thymus.

89
Q

Natural killer cells

A

White blood cells, mature LYMPHOCYTE (agranulocytes), that are part of the innate immune system and are the body’s first line of defense against threats. Develop from lymphoid stem cells. Called “natural” because they can destroy potential threats without prior exposure to a specific pathogen.

90
Q

Monocytes

A

A type of a granulocyte which phagocytize foreign matter such as bacteria. Once they leave the bloodstream and enter an organ they are known as macrophages

91
Q

Macrophages

A

Agranulocyte, monocyte that has entered an organ.

92
Q

Microglia

A

Agranulocyte, macrophage in the central nervous system.

93
Q

Langerhan cells

A

Agranulocyte, macrophage in the skin.

94
Q

Osteoclasts

A

Agranulocyte, monocyte in the bone.

95
Q

Thrombocytes or platelets

A

Cell fragment or shard released from cells and bone marrow known as megakaryocytes. Assist in blood clotting, present in high concentrations.

96
Q

Hematopoiesis

A

Production of blood cells and platelets. Occurs in the bone marrow.

97
Q

Erythropoietin

A

Hormone secreted by the kidney and stimulates mainly red blood cell development (hematopoiesis)

98
Q

Thrombopoietin

A

Hormone secreted by the liver and kidney and stimulates mainly platelet development. Megakaryocyte come from bone marrow and thrombopoietin hormone trigger the production of megakaryocytes that make platelets.

99
Q

Hematopoietic pathways

A
100
Q

-poiesis suffix

A

To form or to make

101
Q

Hemetopoietic stem cell

A

Stem cell that gives rise to all the cells in the blood.

102
Q

Myeloid stem cell

A

Give us rise to:

Granulocyte/monocyte progenitor
Eosinophil progenitor
Basophil progenitor
Megakaryocyte (via thrombopoietin)
Erythroid progenitor (via erythropoietin)

Myeloid means “of or relating to bone marrow”

103
Q

Granulocyte/monocyte progenitor

A

Comes from myeloid stem cell (which arise from hematopoietic stem cell)

Gives rise to:

Monocytes (that become macrophages when they arrive at organs and tissues)

Neutrophil

Dendritic cell

104
Q

Granulocyte/monocyte progenitor

A

Gives rise to:

Monocytes (that become macrophages when they arrive at organs and tissues)

Neutrophil

Dendritic cell

105
Q

Eosinophil progenitor

A

Comes from myeloid stem cell (which arise from hematopoietic stem cell)

Gives rise to eosinophil (GRANULAR leukocyte)

106
Q

Basophil progenitor

A

Comes from myeloid stem cell (which arise from hematopoietic stem cell)

Gives rise to basophils and mast cells (granular leukocytes)

107
Q

Megakaryocyte

A

Comes from myeloid stem cell (which arise from hematopoietic stem cell)

Arise from thrombopoietin hormone (secreted by liver and kidneys) and produce platelets

Karyo in biology refers to the nucleus as it means “nut” or “kernel”

108
Q

Erythroid progenitor

A

Comes from myeloid stem cell (which arise from hematopoietic stem cell)

Arise from erythropoietin (hormone released by kidneys) and creates erythrocytes (red blood cells).

109
Q

Lymphoid stem cell

A

Comes from hematopoietic stem cells. Gives rise to:

Natural killer cells
T progenitors
B progenitor

Lymphoid means relating to or denoting the tissue responsible for producing lymphocytes and antibodies.

110
Q

B progenitor

A

Comes from lymphoid stem cells, which come from hematopoietic stem cells.

Gives rise to B-cells (B lymphocyte) which give rise to plasma cells (plasmacyte)

111
Q

T progenitor

A

Comes from lymphoid stem cell, which comes from hemopoietic stem cells.

Gives rise to T cells (T lymphocyte) which make helper T cell and cytotoxic T cell

112
Q

Two major antigen families relevant for blood groups

A

ABO antigens
Rh factor

113
Q

ABO antigens

A

Comprised of three alleles for blood type. In the particular class of erythrocyte cell surface proteins, the A and B alleles are codominant. The O allele is recessive.

114
Q

Universal donors

A

Individuals with type O blood are considered universal donors because their blood will not cause ABO related hemolysis in any recipient because type O blood cells express neither antigen variant (A or B) And will therefore not initiate any immune response.

115
Q

Individuals with type O (i) blood regarding blood transfusions

A

Individuals with type O (i) blood will produce both anti-A and anti-B antibodies and can only receive type O blood.

116
Q

Universal recipients

A

People with type AB (IA IB) blood are considered universal recipients because they can receive blood from all blood types because no blood antigen is foreign to individuals who have AB blood, so no adverse reaction will occur upon transfusion.

117
Q

Two different ways of writing ABO alleles

A

IA IB and i

A B and O

The former system is more common and medical practice.

118
Q

ABO blood types

A
119
Q

Rh factor

A

Another surface protein expressed on red blood cells. Named Rh because it was first subscribed and rhesus monkeys. Rh-positivity follows autosomal dominant inheritance, meaning one positive allele is enough for the protein to be expressed.

120
Q

Erythroblastosis fatalis

A

A condition where maternal Rh Antibodies attack fetal blood. Rh antibodies are able to cross the placenta.

If a person who is pregnant is Rh- and the fetus is Rh+, The person who is pregnant will be become sensitized to the Rh factor, and the person’s immune system will begin making antibodies against it. This is not a problem for the first child because by the time the person starts producing antibodies, the child has already been born. However, any subsequent pregnancy in which the fetus is Rh+ will present a problem because the maternal anti-Rh antibodies can cross the placenta, and the fetal blood cells, resulting in hemolysis of the fetal cells.

Note that the specific circumstance must occur for erythroblastosis fatalis to occur. Pregnant person must be Rh- with an Rh+ fetus to create antibodies to combat the Rh antigen. Then a subsequent pregnancy with an Rh+ fetus will be dangerous for the fetus. A pregnant person with Rh+ will not endanger a potential fetus.

121
Q

Hypertension

A

High blood pressure

122
Q

Blood pressure

A

Measured of the force per unit area exerted of the blood vessel. Expressed as a ratio of the systole (ventricular contraction) to diastole (ventricular relaxation). Normal blood pressure is considered to be between 90/60 and 120/80.

123
Q

Sphygmomanometer

A

Measure the gauge pressure in the systemic circulation. Measures blood pressure. Inflatable rubber cuff dealy with the bulb thingy and the gauge stuffy.

124
Q

Mean arterial pressure at different locations in the cardiovascular system

A

Pressure gradually drops from the arterial to venous circulation, with the largest drop occurring across the arterioles.

125
Q

Relationship to cardiovascular circulation and pressure to Ohm’s law

A
126
Q

Baroreceptors

A

Specialized neurons located in the walls of the vasculature, specialized neurons that detect changes in the mechanical forces on the walls of the vessel.

When blood pressure gets too low, baroreceptors can stimulate the sympathetic nervous system causing vasoconstriction and thereby increasing blood pressure.

127
Q

Chemo receptors in the vasculature regarding osmolarity

A

Chemo receptors in the vasculature senses when the osmolarity of the blood is too high. This promotes the a release of anti-diuretic hormone (ADH or vasopressin), a peptide hormone made in the hypothalamus stored in the posterior pituitary, which increases the re-absorption of water, thereby increasing blood volume and pressure while also diluting the blood.

128
Q

Renin-angiotensin-aldosterone system

A

A complex system of hormones, proteins, enzymes, and reactions that regulates blood pressure, blood volume, and electrolyte balance. It’s also responsible for systemic vascular resistance. The RAAS is essential for long-term blood pressure regulation.

Ultimately, aldosterone increases the reabsorption of sodium, and by extension water, thereby increasing the blood volume and pressure.

129
Q

Atrial natriuretic peptide (ANP)

A

Think natriuretic-diuretic = natural diuretic

Hormone released from atrial cells that aids in the loss of salt from the nephron within the nephron of the kidneys, acting as a natural diuretic with loss of fluid. ANP also will inhibit the RAAS.

Interesting, ANP is a weak diuretic often not enough to counter the effects of a high salt diet on blood pressure. The human body has many different ways to raise blood pressure, but few ways to lower it.

130
Q

Vital signs

A

Temperature, heart rate, respiratory rate, and blood pressure.

131
Q

Hemoglobin

A

Protein, composed of four cooperative subunits, each of which has a prosthetic heme group that binds to an oxygen molecule. The binding of oxygen occurs at the heme groups central iron atom.

132
Q

Oxygen saturation

A

Percentage of hemoglobin molecules carrying oxygen

133
Q

Cooperative binding of oxygen and hemoglobin

A

The first oxygen binds to a heme group induces a confirmational shift in the shape of hemoglobin that increases the hemoglobin affinity for oxygen making making it easier for subsequent molecules of oxygen to bind to the remaining three un occupied heme groups. Conversely, the removal of one molecule of oxygen will induce a confirmational shift, decreasing the overall affinity for oxygen and make it easier for the molecules of oxygen to the other heme groups.

This is a form of allosteric regulation.

134
Q

Carbonic anhydrase

A

Enzyme which catalyzes the combination reaction between carbon dioxide and water to form carbonic acid.

135
Q

Bohr effect

A

A phenomenon that describes how hemoglobin’s affinity for oxygen decreases when blood pH decreases or carbon dioxide levels increase. This allows hemoglobin to more readily release oxygen into tissues.

Blood pH decreases during times of exercise (lactic acid production), when excess CO2 is present (shifting the bicarbonate buffer reaction to the right) for example.

136
Q

Shifts in the oxyhemoglobin dissociation curve

A

Right shift: Exercise and increase in CO2 and thus a decrease in pH, increase temperature, increase in 2,3-biophosphoglycerate (2,3-BPG, a side product of glycolysis in red blood cells).

Left shift: decrease pressure of CO2 which causes decreased concentration of hydrogen ions, increased pH, decreased temperature, and decreased concentration of 2,3-BPG.

137
Q

Interpretation of the oxyhemoglobin dissociation curve

A

Shift to the right means lower affinity, and hemoglobin will get rid of oxygen to tissues easier.

Shifted the left means higher affinity, and hemoglobin will less readily get rid of oxygen to tissues.

Interesting, fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, and therefore has a left shifted curve compared to adult hemoglobin.

138
Q

Interstitium

A

Interstitial means “between two things”

Cells surrounding the blood vessels, a network of fluid-filled spaces that connects the skin to organs, nerves, and other body parts.

139
Q

Hydrostatic pressure

A

PUSHING FLUID OUT

Force per unit area that the blood exerts against the vessel walls. Generated by the contraction of the heart and the elasticity of the arteries and can be measured upstream in the large arteries as blood pressure.

Hydrostatic pressure pushes fluid out of the bloodstream and into the interstitium through the capillary walls.

140
Q

Osmotic (oncotic) pressure

A

DRAWING FLUID IN

Sucking pressure generated by solute as the attempt to draw water into the bloodstream. Also called oncotic pressure.

Oncotic pressure is osmotic pressure when the pressure is specifically caused by proteins.

Oncotic means “pertaining to swelling”

141
Q

Edema

A

A condition caused by the accumulation of excess fluid in the interstitium

142
Q

Starling forces (regards pressure)

A

Balancing of opposing pressures caused by hydrostatic pressure and osmotic pressure. Understand that the movement of solutes and fluid at the capillary level is governed by pressure differentials, just like the movement of carbon dioxide and oxygen in the lungs.

143
Q

Thoracic duct

A

Largest lymphatic vessel in the body. Located in the thorax and lower neck, runs from abdomen to the junction of the left subclavian and internal jugular veins. Most lymphatic fluid (lymph) is returned to the central circulatory system by way of a channel called the thoracic duct. Blockage of lymph nodes by infection or surgery can also result in edema.

144
Q

Hemophilia

A

Genetic disease, causing malfunction in the cascade of clotting reactions and increase the risk of life-threatening blood loss from injury.

Explained another way: defined medically as an inherited genetic disorder that impairs the body’s ability to make blood clots.

145
Q

Clots

A

Composed of both coagulation factors (proteins) and platelets, and they prevent and or minimize blood loss.

146
Q

Tissue factor (platelet tissue factor)

A

Tissue factor is a protein along with collagen and the underlying connective tissue that trigger platelets of an injury.

147
Q

Coagulation factors

A

Secreted by the liver, sense tissue factor and initiate a complex activation cascade that causes coagulation.

148
Q

Prothrombin

A

Forms thrombin by thromboplastin and then convert fibrinogen into fibrin. Therin ultimately form small fibers that aggregate and cross into a woven structure that captures red blood cells and other platelets for a stable clot over the area of damage.

149
Q

Thrombus

A

Blood clot

150
Q

Plasmin

A

Generated by plasminogen, accomplishes breaking down clots.

151
Q

Sodium Reabsorption

A

Sodium reabsorption is the process by which the kidneys reabsorb sodium ions (Na2+) from the waste products they filter out of the blood, thereby increasing water content of the blood and increasing hydrostatic pressure.

152
Q

Diuretic

A

Reduce fluid buildup in the cardiovascular system, thus reducing blood pressure.

Remember: Atrial natriuretic peptide (ANP) is a peptide hormone produced secreted by the cardiac atria that reduces blood pressure over a slow time.

MCAT Biology Review 2025-26 (16 decks)

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