W2 Cardiovascular Flashcards
State and describe 5 functions of the circulatory system
- Blood carries oxygen fro lungs to tissues and co2 from tissue to lungs.
- Transportation of metabolic wastes to the kidneys
- Transportation of hormones from endocrine organs to target cells
- Prevention of blood loss due to platelets that initiate blood clotting
- Prevention of infection as blood contains antibodies (WBC) helping to destroy microorganisims.
6, maintains normal pH in extracellular fluids due to buffering capacity.
- Regulates body temperature by routing blood to skin
Name and describe the components of the blood
1.Plasma: a clear extracellular fluid 90% water, containing plasma proteins, nutrients, electrolytes, aminoacids, hormones wastes, gases.
Plasma proteins: Albumins - 60% contributes to viscoity and plasma osmotic pressure, carrying stuff.
Globulins (antibodies) provide immune system functions.
Fibrinogen: precursor of fibrin threat, important for blood clots. Plasama proteins are formed by the liver; except globulins
- Formed elements: WBC and platelets Red blood cells. Leukocytes: Neutraphil, Basophils, Eosinophil, Monocytes Adults have 4-6L of blood
Explain the importance of correct blood viscosity and osmolarity
Osmolarity: total molarity of dissolved particles. Low osmolarity: low salt/protein causes fluid absorption into tissues and may result in oedema. Due to excess fluids (dilutes solutes) = ↑ BP. (↓ salt ↓ protein) High osmolarity: high salt/protein causes absorption into blood. Due to fluid loss (dehydration) ↓ BP (↑ salt ↑ protein)
Describe the structure and function of erythrocytes and their relationship to haemoglobin
RBC have no nucleus and are shaped like dipped disc. Contain hemoglobin. ↑ surface area in comparison to volume ↑ diffusion rate. Major function in the transport of o2 transport to tissues and lungs Hemoglobin (Hb) is an iron/protein pigment, it can carry four 02 and binds to an o2 iron to transport blood. Releases oxygen when pH changes in blood.
Define haematocrit
The oxygen carrying capacity of blood is influenced by the number of red blood cells and the amount of haemoglobin each red blood cell contains. % amount of RBC found in a sample.
↓ Hct - anemia - lack of RBC ↓ profuction/in↑ loss of RBC. Symptoms of weakness and fatigue.
↑ Hct - polycythaemia - due to ↓ plasma or ↑ RBCs, makes blood thick and sticky, ↑ bp MEN 42-52% 13-1g/dL WOMEN 37-48% 12-16g/dL
Describe the life cycle of red blood cells including their production and disposal
Erythropoiesis is the entire process (3-5 days) of RBC formation, it is a hormone produced by the kindey in response to hyoxia (↓ o2) that stimulates RBC production. Erythrocytes cannot continue to synthesise proteins, divide/reproduce. Life space typically <120 days. Replaced from red bone marrow.
Stimulates erythropoieses: ↓ o2, ↑ exercise. Passes through the spleen crack and fragments RBC - macrophages digest these for disposal.
[Hemoglobin in broken down → heme + globin]
What are the structures of the circulatory system
Blood, blood vessels, the heart
Explain what determines a person’s ABO blood type
Antigens: foreign molecule (lock and key). These are recognized by antibodies or immune cells so they can be destroyed. Antibodies: are antigen recognition sites ‘ Y ‘ Agglutination: antigens and antibodies clumping together and binding. A, B, AB, O antigens.
Determine what blood types are compatible/incompatible with each other and understand the concepts of universal donor/recipient
Compatibility: When mixing donor and recipient blood of the same tye (a) occurs, there is NO agglutination because only anti-B antibodies are present. A mixed with A = A okay!
Incompatible: If type A donor blood is mixed with type B recipient blood, agglutination due to anti-A antibodies in the type B recipients blood. A mixes with B = A Bad Mix.
2 Major consequences of transfusion reaction”
1) Antibody targeted RBCS are attached by host defense mechanisim and haemolyse (burst). Free Hb block kindey tubules causing death.
2) Agglutinated RBS block vessels reducing nutrient and o2 supply to tissues.
Explain what determines a person’s Rh blood type
Rh (D) agglutinogens. Rh+ or Rh- refering to the presense or adsence of the D agglutiongen (antigen). Must be exposed to Rh+ to have it.
Explain haemolytic disease of the newborn, why it occurs and how to prevent it?
Due to Rh blood type of the mother and the Rh blood type of the father. Rh blood type incompatibility between mum and child. ONLY occurs in the 2nd pregnancy.
[Rh- mum has formed antibodies and is preg with 2nd Rh+ child] Prevention: RhoGAM given to pregnant women.
Describe the structural characteristics and functions of each of the five leukocytes
Travel in the blood then migrate to connective tissue. (NEVER)Neutrophils: target bacteria and fungi, 1st at scene (LET)Lymphocytes: B cells antibodies. T cells cytotoxic, NK cell kill abnormal (MONKEYS)Monocytes: migrate into tissues → phagocytosis (EAT) Eosinophils: target, parasites, worms. modulate aleergie inflamm (BANANAS)Basophils: release histamine to promote inflammation Granulocytes Agranulocytes
Describe platelets and list 5 functions
Platelets are cell fragments of a large red bone marrow cell called megakaryocyte. Formation of platelets = thrombopoiesis. Agglutination, Adhesiveness, Aggregation. ↓ count = thrombocytopenia. Life span 7 days. 1. Seal small breaks in injured blood vessels. 2. Secretion of chemical that cause vasoconstriction of broken cell walls. 3. Secretion of clotting factors which promote blood clotting. 4.Secrete growth factors 5. Secrete chemicals that attrach nutrophils and monocytes for inflammation. 6. Initiate formation of clot-dissolving enzyme.
Name and describe the 1st of the 3 haemostatic mechanisms
Vascular spasm: the bodies immediate reponse is to constrict the damaged blood vessel. Triggered by:
- Direct injury to vascular smooth muscle
- Serotonin released by platelets
- Endothelin released by endothelial cells reflexes initiated by local pain receptors.
- Resulting in constricted blood vessel to reduce blood loss.
[exposed collagen = platelet binding, vasoconstriction occurs, plate aggrigation]
Name and describe the 2nd of the 3 haemostatic mechanisms
Platelet plug formation: only adhere to exposed damaged collagen site and change shape, degranulate and release chemicals such as serotonin, thrombonxane and ADP, forming a platelet plug. Positive feedback loop.
Name and describe the 3rd haemostatic mechanism including both the intrinsic and extrinsic pathways
Coagulation cascade 1. Clot formation: conversion of plasma protein fibrinogen into insoluble fibrin thread to form framework of clot 2. Fibrin: activation of clotting factor 10 X → thrombin → fibrinogen → fibrin mesh
Define and distinguish between the pulmonary and systemic circuits
Pulmonary circuit: RHS of ❤ carries deoxygenated blood to the lungs via L & R pulmonary arteries for gas exchange and oxygenated blood back to the heart via the 4 pulmonary veins. ↓ pressure system.
VS
Systemic circuit: LHS of ❤ supplies oxygenated blood to all organs via aorta and bring back deoxygenated blood from tissues into R attrium via superior and inferior cava. ↑ pressure system
Name and describe the 3 layers of the heart wall
Epicardium - serous membrane covers heart
Myocardium - outter muscular layer.
Endocardium: smooth inner lining of epithelial tissue
Name, describe, identify and state the function, of the 4 heart chambers
Left and Right Atria
Two superior chambers receive blood from veins. Relax to receive and contract to push blood. (Atria myocardium have thinner myocardium).
Left and right ventricles
Two inferior chambers known as pumping chambers, they push blood into the large network of vessels. (Ventricular myocardium have thicker myocardium)
Internal: Interatrial septum wall that separates aria
Pectinate muscles: internal ridges of myocardium in right atrium and both auricles. Interventricular septum: wall seperating ventricales
Trabculae carneae internal ridges in both ventricles
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Name , identify and describe function of the 4 heart valves
The role of the valves is to prevent backflow of blood through the heart in one direction. Bicuspid (mitral) valve: between the left atrium and left ventricle.
Right AV (tricuspid) valve: between the right atrium and right ventricle
Aortic semilunar valve: start of the aorta
Pulmonary semilunar valve: start of the pulmonary trunk.
Semilunar valve: at the start of arteries, 3 cusps one way valve, prevent backflow in ventricles.
Atrioventricular valve: LHS bicusp, RHS tricusp; stops back flow intro atria
Mechanics of ventricles
Ventricles relax → pressure drops → semilunar valve closes → AV valve open → blood flows from atria to ventricles.
Ventricles contract: AV valve close → pressure rises → semilar valve opens → blood flows into great vessels
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Trace the flow of blood through the chambers, valves and vessels of the heart
Body
↓ Vena Cava
↓R atrium
↓R AV valve
↓ R ventricle
↓ Pulmonary semilunar valve
↓ pulmontory trunch
LUNGS → Pulmonary veins →left atrium →left AV valve → left ventricle → aortic SL valve → aorta → BODY
Name and describe the arteries that nourish the myocardium and the veins that drain it
Myocardial cells receive blood from R L coronary arteries. 1st branch to come off the aorta → ventricles receive blood from a small branch of the corresponding coronary artery.
Most abundant blood supply goes to the myocardium of left ventricle. Cardiac veins follow a course parallel to coronary arteries, after passing through the cardic ceins deoxygenated blood enters coronary sinus to brain into the right atrium
