Biology Ch 7. The Cardiovascular System Flashcards
Cardiovascular system
Consists of the heart, blood vessels, and blood
Heart
Composed of cardiac muscles and supports both the pulmonary and systemic circulation, four chambers, both sides have an atrium and a ventricle, left side has more muscle than right because the systemic circulation has a much higher resistance and pressure
Pulmonary circulation
Circulation system from the right ventricle to the lungs and then back to the left atrium
Systemic circulation
Circulation system throughout the body from the left ventricle and finally back to the right atrium
Atrioventricular valves
Separate the atria from the ventricles, tricuspid (three leaflets) on the right and mitral (bicuspid, two leaflets) on the left
Semilunar valves
Separate the ventricles from the vasculature, pulmonary on the right and aortic on the left, allow the heart to create the pressure within the ventricles necessary to propel blood forward within the circulation while also preventing back flow, both three leaflets
Blood pathway
Right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary artery, lungs, pulmonary veins, left atrium, mitral valve, left ventricle, aortic valve, aorta, arteries, arterioles, capillaries, venules, veins, vena cava, right atrium
Electrical conduction of the heart
SA node, AV node, Bundles of His, Purkinje fibers
Sinoatrial node
SA node - where electrical conduction of the heart starts, generates 60-100 signals per minute without requiring any neurological input, small collection of cells located in the wall of the right atrium, causes two atria to contract simultaneously
Atrioventricular node
AV node - sits at the junction of the atria and the ventricles, signal delayed here so that the ventricles can fill completely before they contract
Bundles of His
Has branches embedded in the inter ventricular septum (wall)
Purkinje fibers
Distribute the electrical signal through the ventricular muscle
Systole
Results in an increase in atrial pressure that forces a little more blood into the ventricles then the AV valves are closed
Diastole
Period where the heart is relaxed and the semilunar valves are closed
Cardiac output
Product of heart rate x stroke volume, about 5 liters per minute for humans
Parasympathetic and sympathetic nervous system cardiac output
Sympathetic NS increased the heart rate and contractility, parasympathetic NS decreases heart rate
Vasculature
Consists of arteries, veins, and capillaries
Arteries
Thick, highly muscular structures with an elastic quality (high resistance to blood flow), allows for recoil and helps to propel blood forward within the system, blood travels away from the heart, largest is aorta , branch into arterioles, much more smooth muscle than veins, most oxygenated except pulmonary and umbilical
Arterioles
Small muscular arteries which control flow into capillary beds
Capillaries
Have walls that are one endothelial cell thick, very narrow and red blood cells must travel through them single file, site of gas, nutrient, and waste exchange, interface for communication of the circulatory system and tissues, delicate and when damaged, blood can enter interstitial space and result in bruise
Veins
Inelastic, thin-walled structures that transport blood to the heart, they are able to stretch in order to accommodate large volumes of blood but do not have recoil capability, are compressed by surrounding skeletal muscles and have valves to maintains one way flow, carry deoxygenated blood other than pulmonary veins and umbilical vein
Venules
Form from joined capillaries, join into veins
Portal system
A system in which blood passes through two capillary beds in series, not typical because usually blood only passes through one
Hepatic portal system
Blood travels from the gut capillary beds to the liver capillary bed via the hepatic portal vein
Hypophyseal portal system
Blood travels from the capillary bed in the hypothalamus to the capillary bed in the anterior pituitary
Renal portal system
Blood travels from the glomerulus to the vas recta through an efferent arteriole
Atria
Thin walled structures where blood is received from either the venae cavae
Ventricles
Send blood to lungs and the systemic circulation, more muscular than the atria
Atrial kick
Additional blood forced into the ventricles during atrial systole, accounts for only 5-30% of cardiac output because most ventricular filling is passive
Interventricular septum
Wall where bundle of His are embedded
Intercalated discs
Connects muscle cells, contain many gap junctions directly connecting the cytoplasm of adjacent cells, allows for coordinated ventricular contraction
Vagus nerve
Nerve through which parasympathetic signals travel to the heart slowing down the heart rate
Blood vessel endothelial cells
Endothelial cells lines all blood vessels, helps to 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, also release chemicals when damaged that are involved in the formation of blood clots to repair the vessel and stop bleeding
Venae cavae
Returns blood to right atrium of heart, divided into superior and inferior vena cava
Blood
Composed of cells and plasma
Erythrocyotes
aka red blood cells, lack mitochondria, a nucleus, and organelles in order to make room for hemoglobin, have biconcave shape to increase SA and for easier travel through capillaries, do not consume oxygen, get ATP via glycolysis, unable to divide
Hemoglobin
A protein that carries 4 oxygens, on erythrocytes
Hematocrit
The percentage of blood composed of erythrocytes
Leukocytes
aka white blood cells, are formed in the bone marrow, crucial part of the immune system, divided into granular and agranulocytes
Granular leukocytes
Contain cytoplasmic granules which contain a variety of compounds that are toxic to invading microbes, includes neutrophils, eosinophils, and basophils, play a role in nonspecific immunity especially inflammatory reactions, allergies, pus formation, and destruction of bacteria and parasites
Agranulocytes
Includes lymphocytes and monocytes, plays a role in immunity
Thrombocytes
aka platlets, cell fragments from megakaryocytes that are required for coagulation
Megakaryocytes
Type of cell in bone marrow that creates thrombocytes
Blood ABO antigens
Surface antigens A, B, and O, IA and IB alleles are codominant while the I allele is recessive, an individual has antibodies for any AB alleles they dont have
Plasma
An aqueous mixture of nutrients, salts, respiratory gases, hormones, and blood proteins
Blood cells
Erythrocytes, leukocytes, and platelets, all formed from hematopoietic stem cells in the bone marrow
Lymphocytes
Play a large role in specific immunity, includes B and T cells
Specific immune response
The body’s targeted fight against particular pathogens such as viruses and bacteria
B cells
Mature in the bone marrow, responsible for antibody generation
T cells
Mature in the thymus, kill virally infected cells and activate other immune cells
Monocytes
Phagocytize foreign matter such as bacteria, renamed as macrophages once they leave the bloodstream and enter an organ
Macrophages
Monocytes that have entered an organ from the bloodstream, called microglia in the CNS, Langerhans cells in the skin, and osteoclasts in the bone
Hematopoiesis
The production of blood cells and platelets, triggered by a number of hormones, growth factors, and cytokines
Erythropoietin
Secreted by the kidney and stimulates mainly erythrocyte development
Thrombopoietin
Secreted by the liver and kidney and stimulates mainly platelet development
Rh factor
Also surface protein on red blood cells, the positive Rh factor is dominant and a negative individuals will only create anti Rh antibodies after exposure to Rh positive blood, makes for complications such as erythroblastosis fetalis during childbirth
Antigens
Surface proteins expressed by red blood cells, any specific target to which the immune system can react
Universal donors
People with type O blood because their blood will not cause an ABO related hemolysis in any recipient, they express neither antigen variant
Universal recipients
People with type AB blood because they can receive blood from all blood types
Erythroblastosis fetalis
Condition where Rh- maternal anti-Rh antibodies cross the placenta and attack fetal blood cells, can be lethal, medication can treat, not a problem for first child because mom does make anti-Rh antibodies until exposed to Rh+ the first time, bigger issue that ABO because anti-Rh IgG antibodies can cross placenta while AB IgM antibodies cannot
Blood pressure
The force per unit area that is exerted on the walls of blood vessels by blood, divided into systolic and diastolic components, must be high enough to overcome the resistance created by arterials and capillaries, but low enough to avoid damaging the vasculature and surrounding structures, measured by sphygmomanometer, maintained by baroreceptor and chemoreceptor reflexes
Sphygmomanometer
Can measure blood pressure, measures gauge pressure
Low blood pressure
Promotes aldosterone and antidiuretic hormone (ADH or vasopressin) release
High blood pressure
Promotes atrial natriuretic peptide release
Antidiuretic hormone
ADH - aka vasopressin, released because of low blood pressure or high blood osmolarity, peptide hormone made in hypothalamus but stored in posterior pituitary, causes increased reabsorption of water
Atrial natriuretic peptide
ANP - hormone released by special atrial cells in response to high blood pressure, aids in the loss of salt within the nephron, weak natural diuretic
Starling forces
Consist of the balancing between hydrostatic and osmotic pressures, essential to maintain the proper fluid volumes and solute concentrations inside and outside the vasculature
Hydrostatic pressure
The pressure of the fluid within the blood vessel, generated by the contraction of the heart and the elasticity of the arteries, forces fluid out at the arteriolar end of a capillary bed (forces water out of circulation)
Osmotic pressure
The “sucking” pressure drawing water toward solutes
Onconic pressure
Osmotic pressure due to proteins, draws fluid back in at the venule end of capillary beds
Cooperative binding
Form of allosteric regulation, type of binding by which hemoglobin carries oxygen, each successive oxygen bound to hemoglobin increases the affinity of the other subunits, while each successive oxygen released decreases the affinity of the other subunits
Oxygen hemoglobin binding
Cooperative binding, in the lungs, high partial pressure of oxygen resulting in the loading of oxygen onto hemoglobin, in the tissues, low partial pressure of oxygen resulting in unloading, much occur because oxygen not soluble
Carbon dioxide blood stream
Carried in the form of carbonic acid or bicarbonate and hydrogen ions because carbon dioxide non polar and not particularly soluble, carbon dioxide catalyzed into carbonic acid by carbonic anhydrase, bicarbonate buffer
Oxyhemoglobin dissociation curve
S-shaped curve that is a result of cooperative binding, reflects affinity for oxygen, a high air partial pressure of CO2, high H+ concentration, low pH, high temp, and high concentration of 2,3 BPG will cause a right shift in the curve, reflecting a decreased affinity for oxygen, left shift in curve for fetal hemoglobin
Coagulation cascade
Results from an activation cascade when the endothelial lining of a blood vessel is damaged and collagen and tissue factor are exposed, ultimately results in the formation of a clot over the damaged area
Tissue factor
Protein that becomes exposed during blood vessel damage and are detected by coagulation factors to trigger coagulation cascade
Fibrin
Stabilize platelets that bind to the collagen during coagulation cascade, activated by thrombin, forms small fibers that aggregate and cross link into a woven net structure, captures red blood cells and platelets, forms stable clot over area of damage
Thrombin
Coverts fibrinogen to fibrin, formed because of the activation of prothrombin by thromboplastin
Plasmin
Breaks down clots, generated by plasminogen
Pressure differential across circulation
Cardiac output x total peripheral (vascular) resistance
Blood pressure baroreceptors
In walls of vasculature, can stimulate sympathetic nervous system to vasoconstrict, increasing blood pressure
Blood pressure chemoreceptors
Can sense osmolarity of the blood, promote release of aldosterone, ADH, or ANP
Aldosterone
Increases the reabsorption of sodium, and by extension water, thereby increasing the blood volume and pressure
Hemoglobin
A protein composed of four cooperative heme subunits that each bind to an oxygen molecule, conformational change from taut to relaxed occurs with first binding of oxygen and changes back after first oxygen leaves
Oxygen saturation
the percentage of hemoglobin molecules carrying oxygen, normal above 97%
Bohr effect
Decreased affinity for oxygen that occurs because decreased pH, which decreases affinity (a right shift in the oxyhemoglobin curve)
Decreased oxyhemoglobin affinity
Allows for more oxygen to be unloaded at the tissues
Fetal hemoglobin (HbF)
Has a higher affinity for oxygen than adult hemoglobin, shifts oxyhemoglobin curve to the left
Edema
Accumulation of excess fluid in the interstitial
Lymph
Lymphatic fluid, returned to the central circulatory system by the thoracic duct, blockage of nodes can result in edema
Thoracic duct
Channel that returns lymph to the central circulatory system
Clot
Composed of both coagulation factors and platelets, prevent (or minimize) blood loss
Coagulation factors
Most secreted by the liver, sense tissue factor and initiate coagulation cascade
Plasminogen
Generates plasmin
Prothrombin
Forms thrombin by thromboplastin
Fibrinogen
Converted to fibrin by thrombin during coagulation cascade
