Cardiovascular System Flashcards
What are the 3 parts that make up blood?
Plasma, buffy coat and hematocrit.
What is plasma made up of?
Water, proteins, nutrients, hormones etc…
What is buffy coat made up of?
White blood cells and platelets
What is hematocrit made up of?
Red blood cells
What is the normal blood % of hematocrit?
40%-50% Women
40 - 60% Men
What is anaemia in terms of hematocrit?
Depressed hematocrit
What is polycythemia?
Elevated hematocrit levels
What is haematopoiesis?
Blood cell production
How does haematopoiesis start?
With a multipotent haematopoietic stem cell (hemocytoblast), then these cells can turn into 2 things depending on chemical messages.
What are the 2 things that multipotent haematopoietic stem cell (hemocytoblast) turn into (first step of haematopoiesis)?
Either they turn into myeloid or lymphoid stem cells. Some just remain stem cells.
What does a lymphoid stem cell turn into?
Lymphoblast
What do lymphoblasts turn into?
- Natural killer cells (large granular lymphocytes).
- Small lymphocytes:
- T lymphocyte
- B lymphocyte
What do myeloid stem cells turn into?
- Megakaryocyte
- Proerythrocyte
- Myeloblast
- Monoblast
What do megakaryoblasts turn into?
Megakaryocyte and then into platelets.
What do proerythrocytes turn into?
Reticulocyte then to erythrocytes (RBC).
What do myeloblasts turn into?
- Basophil
- Neutrophil
- Eosinophil
What do monoblasts turn into?
Monocyte
What is erythropoietin?
EPO stimulates red blood cell production.
Where is EPO produced/secreted?
Secreted by kidney fibroblasts in response to low oxygen.
What is thrombopoeitin?
Triggers megakaryocytes to turn into platelets.
Where is thrombopoeitin produced?
Kidney and liver, its a hormone.
What are cytokines?
They trigger the proliferation (rapid increase) of progenitor cells.
They also stimulate specific and non-specific disease resistance.
What are progenitor cells?
A dividing cell that has the ability to differentiate into different cell types. Like the multipotent hematopoietic setm cell (hemocytoblast).
Where are cytokines produced?
Cytokines are produced by bone marrow, leukocytes, macrophages, fibroblasts and endothelial cells.
What are the 2 cytokine substances?
Colony stimulating factors (CSFs) and interleukins (IL-).
What is the function of colony stimulating factors?
They act locally as autocrine or paracrine factors, different CSFs trigger different WBC development.
What are autocrine factors?
A factor secreted by a cell and act on the same cell that produced them.
What are paracrine factors?
Factors that are secreted by a cell and act on nearby cells in the local environment.
What are interleukins (IL)?
They’re produced by bone marrow and endothelium. Their functions include differentiation and maturation of cells, producing immunity and inflammation.
Explain the structure of a RBC (components)?
4 globin proteins bound to 1 Fe-containing pigment: haem.
What is the avergae lifespan of a RBC?
120 days
What happens to old and damaged erythrocytes?
They are phagocytized by macrophges in the bone marrow, liver and spleen.
What happens to the globin portion of hameoglobin?
The globin portion is metabolised into amino acids, which are then reused fro protein synthesis.
What happens to the heme portion of haemoglobin?
The heme is broken down into biliverdin for transport in the blood. This biliverdin then turns into bilirubin and is used to make bile in the liver. The heme can also be recycled and used in haematopoiesis.
What happens to the iron portion of haemoglobin?
The iron ions bind to the blood protein transferrin for transport. Then are stored in the liver.
What are the granular blood cells?
Neutrophils, eosinophils and basophils.
What is order of most to least common of granular WBCs?
- Neutrophils
- Eosinophils
- Basophils
What is the lifespan of granular WBCs?
Hours - days
What are the granular WBCs?
Monocytes, macrophages and lymphocytes.
What is the lifespan of Agranular WBCs?
These memory cells have a lifespan of years.
What are leukocytes?
white blood cells
What are neutrophils?
Most abundant WBC 50-70% of all WBCs. Innate immunity. They are phagocytic and release chemicals from granules.
What are eosinophils?
WBCs, phagocytic. Specialise in combating parasitic infections and mediating allergic reactions. They release antihistamines.
What are basophils?
WBCs, similar to eosinophils in regards to antihistamines and parasitic infections but mainly focsued on promoting inflammation.
What does granular mean?
Non specififc or innate, bodies first line of defense. Present at birth.
What are agranularc leucocytes?
Body defenses, they have specific roles.
What are the different types of lymphocytes and their functions?
- T cells - attack other cells.
- B cells - release antibodies.
- Natural Killer cells, are similar to T cells but non-specific.
What are lymphocytes specific function?
Primarily specific (adaptive immunity). Aquired after being exposed to antibodies.
What are monocytes?
Effective phagocytes, they are anitgen presenting cells. They are called macrophages once they leave the blood.
What is the function of platelets?
They have a role in haemostasis, they help to clot blood. Granules release growth factors for repair and healing of tissue.
Where are platelets stored?
1/3 stored in spleen for release.
What is the life cycle of platelets?
10 days
Which side of the heart contains low levels of oxygen?
Right - the pulmonary circuit
Which side of the heart contains high levels of oxygen?
Left - systemic circuit
What are the layers of the heart muscle called?
From inner to outer:
- Endocardium
- Myocardium
- Epicardium (visceral layer of serous pericardium)
- Pericardial cavity
- Parietal layer of serous pericardium
- Fibrous pericardium
Where is the fluid in the heart wall?
In the pericardial cavity between the epicardium an d parietal layer of serous pericardium.
What is the thickest layer in the heart wall?
The myocardium or the muscular layer.
What side of the heart has thicker muscle and why?
The left ventricle has thicker muscle as the blood has a longer path to travel.
What are the coronary arteries?
The blood vessels that supply the heart muscle with oxygen rich blood. They start at the very first part of the aorta (carries blood out of the heart from the left ventricle).
Where is the sinoatrial node known as?
The pacemaker
Where is the SA node found?
At the top of the right atrium in close proximity to the superior vena cava.
What is the trigger for muscular contraction in terms of the SA node?
The electrical event, the wave of depolarisation.
What is the function of the AV node?
It receives the electrical impulse from the SA node, delays the signal briefly (100ms) before passing it on to the ventricles.
This delay ensures the atria have time to contract and push blood into the ventricles before the ventricles contract.
What are purkinje fibres?
Muscle fibers that carry electrical impulse and cause the heart to beat.
What is the structure of an artery?
Small tunica externa and intima, large tunica media.
What is the structure of a vein?
Large tunica externa, large tunica media and small tunica intima.
Where are elastic arteries found and what are their function?
Closest to the heart, they handle the highest pressure, they need to expand and recoil well. They have a VERY large tunica media.
What are muscular arteries and what are their function?
They have lower pressure, so less need to expand. They mainly distribute blood.
What are arterioles and what are their function?
Very small and linked to capillaries, they have very low pressure, they are critical in blood pressure control.
