Ch. 7: The Cardiovascular System Flashcards
Cardiovascular System
Consists of a muscular 4 chambered heart, blood vessels, and blood
Heart
Composed of cardiac muscle and supports 2 diff circulations– pulmonary circulation and systemic circulation
Each side of the heart has
An atrium and a ventricle
The atria are separated from the ventricles by
Atrioventricular valves: tricuspid on the right and bicuspid/mitral on the left
Ventricles are separated from the vasculature by
Semilunar valves: pulmonary on the right, mitral on the left
What is the pathway of blood in the heart
- right atrium
- right ventricle via tricuspid valve
- pulmonary artery via pulmonary valve
- lungs
- pulmonary veins
- left atrium
- left ventricle via mitral valve
- aorta via aortic valve
- arteries
- arterioles
- capillaries
- venules
- veins
- venae cavae
- right atrium
Left side of the heart contains more muscle
Than the right side because the systemic circulation has a much higher resistance and pressure
Electrical Conduction of the Heart
Starts at the sinoatrial (SA) node and then goes to the atrioventricular (AV) node. From the AV node, electrical conduction goes to the bundle of His before traveling through the purkinje fibers
Systole
Refers to the period during ventricular contraction when the AV valves are closed
Diastole
The heart is relaxed and the semilunar valves are closed
Cardiac Output
Product of heart rate and stroke volume
Sympathetic Nervous System
Increases the heart rate and contractility
Parasympathetic Nervous System
Decreases the heart rate
Vasculature
Consists of arteries, veins, and capillaries
Arteries
Thick, highly muscular structures with an elastic quality. This allows for recoil and helps to propel blood forward within the system.
Arterioles
Small muscular arteries which control flow into capillary beds
Capillaries
Have walls that are one cell thick, making them so narrow that red blood cells must travel through them in a single-file lines. Capillaries are the sites of gas and solute exchange
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. Veins are compressed by surrounding skeletal muscles and have valves to maintain one-way flow
Venules
Small veins
Portal System
One in which blood passes through 2 capillary beds in series
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 hypothalamus to the anterior pituitary
Renal Portal System
Blood travels from the glomerulus to the vasa recta through an efferent arteriole
Blood Composition
Cells and plasma, an aqueous mix of nutrients, salts, respiratory gases, hormones and blood proteins
Erythrocytes
Red blood cells, lack mitochondria, a nucleus, and organelles in order to make room for hemoglobin
Hemoglobin
A protein that carries oxygen
Common measurements
Hemoglobin concentration and hematocrit– percentage of blood composed of erythrocytes
Leukocytes
White blood cells, formed in the bone marrow, crucial part of the immune system
Granular Leukocytes
Neutrophils, eosinophils, and basophils play a role in nonspecific immunity
Agranulocytes
Include lymphocytes and monocytes also play a role in immunity– lymphocytes play a large role in specific immunity
Thrombocytes
Platelets, cell fragments from megakaryocytes that are required for coagulation
Blood Antigens
Surface antigens A, B, and O as well as Rh factor (D)
Blood Alleles
I^A (A) and I^B (B) alleles are codominant, while the i (O) allele is recessive. An individual has antibodies for any AB alleles he or she does not have. Positive Rh factor is dominant. An Rh-negative individual will only create anti-Rh antibodies after exposure to Rh positive blood
Blood Pressure
Refers to force per unit area that is exerted on the walls of blood vessels by blood. Divided into systolic and diastolic components. BP must be high enough to overcome resistance created by arterioles and capillaries, but low enough to avoid damaging the vasculature and surrounding structures
Sphygmomanometer
Measures BP
BP maintenance
Maintained by baroreceptor and chemoreceptor reflexes. Low BP promotes aldosterone and antidiuretic hormone (ADH or vasopressin) release. High blood osmolarity also promotes ADH release. High BP promotes atrial natriuretic peptide (ANP) release
Gas and Solute Exchange
Occurs @ the level of the capillaries and relies on the existence of concentration gradients to facilitate diffusion across the capillary walls. Capillaries are also leaky, which aids in transport of gases and solutes
Starling Forces
Consist of hydrostatic pressure and osmotic (oncotic) pressure. Hydrostatic pressure is the pressure of the fluid within the blood vessel, while osmotic pressure is the “sucking” pressure drawing water toward solutes. Oncotic pressure is osmotic pressure due to proteins. Hydrostatic pressure forces fluid out at the arteriolar end of a capillary bed; oncotic pressure draws it back in at the venule end
Cooperative Binding
Oxygen is carried by hemoglobin which exhibits cooperative binding. In the lungs, there is high partial pressure of oxygen, resulting in loading of oxygen onto hemoglobin. In the tissues, there is a low partial pressure of oxygen, resulting in unloading. With cooperative binding 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
Cooperative Binding
Oxygen is carried by hemoglobin which exhibits cooperative binding. In the lungs, there is high partial pressure of oxygen, resulting in loading of oxygen onto hemoglobin. In the tissues, there is a low partial pressure of oxygen, resulting in unloading. With cooperative binding 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
Carbon Dioxide in the Blood
CO2 is largely carried in the blood in the form of carbonic acid, or bicarbonate and hydrogen ions. CO2 is nonpolar and not particularly soluble, while bicarbonate, hydrogen ions, and carbonic acid are polar and highly soluble
Oxyhemoglobin Dissociation Curve
A high PaCO2, High [H=], high temp and high concentration on 2,3-BPG can cause a right shift, reflecting a decreased affinity for oxygen. Opposite to these causes, a left shift can also be seen in fetal hemoglobin compared to adult hemoglobin.
______, _____, and _____ are carried in the bloodstream to tissues for use of disposal
Nutrients, wastes, and hormones
Coagulation
Results from an activation cascade
Tissue factor
When the endothelial lining of a blood vessel is damaged, the collagen and tissue factor underlying the endothelial cells are exposed.
Coagulation Cascade
Result of damage of endothelial lining of a blood vessel, resulting in the formation of a clot over the damaged area
Fibrin
Platelets bind to the collagen and are stabilized by fibrin, which is activated by thrombin
Plasmin
Clots can be broken down by plasmin
