TP6 Cardiovascular System Flashcards
Lists the products blood transports
Carries:
- Nutrients from digestive tract and liver to body
tissues
- O2 from lungs to peripheral tissues and CO2 from
peripheral tissues to lungs
- Hormones from endocrine glands to target organs
and tissues
- Waste products from various tissues to kidneys for
excretion
List the other functions of blood
- heat and assists in thermoregulation
- regulates pH and ion composition of interstitial fluids
- Clots to restrict fluid loss and begin injury repair
- defends against toxins and pathogens
How is blood quality measured
Packed Cell Volume (PCV): measures % of RBC’s in the blood
List the major components of blood
- Erythrocytes (RBC’s)
- Leucocytes (WBC’s)
- Platelets
Describe the buffy coat
Made up of WBC’s and platelets
Describe the properties of blood
viscosity: 5x the amount of water
temp: slightly above that of the body
pH: slightly alkaline (7.4 +/- 0.05)
volume: 8-10% lean body weight of animal
Describe Haematopoiesis
Formation and development of all formed elements
Describe RBC’s (5 pts)
- No nuclei or mitochondria
- Most abundant cells in blood
- Can distort temporarily and elastically to pass through small capillaries
- specialised for O2 transport
- Shape provides larger S.A.:V = faster O2 exchange across cell membrane
Describe Erythropoiesis
Formation of RBC’s
Where are RBC’s formed in adults and foetus?
In adults, RBC’s are formed in the red bone marrow, and in a foetus, RBC’s are formed in bone marrow, liver, spleen and lymph nodes
Name the HGF that stimulates RBC formation
Erythropoietin (EPO): released from specific cells in the kidney when under O2 stress
Describe the steps in RBC production
- Kidneys detect less O2
- When less O2 is delivered to the kidneys, erythropoietin secreted
- Erythropoietin stimulates erythropoiesis by bone marrow
- Additional RBC;s increase O2 carrying capacity
- Increased O2 capacity = initial stimulus relieved
Describe the components of RBC’s
- Haemoglobin (Hb)
- Carbonic anhydrase
Describe the structure of Hb
- 4x red porphyrin pigments (heme) - gives cells red colour
- Each heme group contains Fe atom - combines loosely with O2 molecule
Describe the function of Hb
- Transports O2 as oxyhaemoglobin
- Can also transports CO2 as carbaminohaemoglobin
Describe Myoglobin
- muscle Hb
- Only has 1x heme group
- Temporary O2 storage
Describe the steps in the removal of RBC’s
- Broken down by macrophages in the spleen and liver
- Hb broken down into heme and globin
- Fe separated from heme
- Heme then converted to biliverdin (green pigment), then bilirubin (yellow pigment)
- Excreted in bile or urine
Describe the role of the spleen in RBC removal
Spleen filters, removes, and stores old erythrocytes
Describe the role of the liver in RBC removal
Metabolises by-products from the breakdown of RBC’s
Describe the cause of anaemia
Reduction in number of RBC’s, hb, or both
Describe the characteristics of Leucocytes
- Carry out functions in tissues
- Use circulatory system for transport
- Have nucleus and cytoplasm
List the two classifications of leucocytes
Granulocytes - with granules in cytoplasm
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes - no granules in cytoplasm
- Monocytes
- Lymphocytes
Describe neutrophils
- Stain colourless - pale pink
- Multilobulated or segmented nucleus
- First line of defence against infection
Describe Eosinophils
- Stain bright pink
- Nucleus less lobulated
- Slightly phagocytic
- Respond to allergic reactions and parasitic infections
Describe Basophils
- Stain Blue
- Not phagocytic
- Release histamine, heparin, bradykinin during inflammatory reactions
Describe Monocytes
- Motile - travel to sites of inflammation
- Develop into very active phagocytic cells known as macrophages
Describe Lymphocytes
- Produced from stem cells in bone marrow
- Mature in lymphoid tissues
- Large, round nucleus
List the two types of lymphocytes
- B-lymphocytes (B-cells)
- T-lymphocytes (T cells)
Describe B-lymphocytes
- Mature in bone marrow
- Differentiate into plasma cells that produce antibodies to destroy foreign material
Describe T-lymphocytes
- Mature in the Thymus
- Do not produce antibodies
- several types include: cytotoxic T-cells, Helper T-cells, Suppressor T-cells
Describe platelets (3 pts)
- No nuclei
- In non-mammalian vertebrates, are nucleated, called thrombocytes
In adult mammal, originate from megakaryocytes, by budding off pieces of cytoplasm - Important in blood clotting
List the steps in the blood clotting process
- Vascular phase
- Platelet phase
- Coagulation phase
Describe the second step of the blood clotting process
- Platelets attach to the sticky endothelial membranes forming platelet plug
- Platelets contain high conc. of actin and myosin
More platelets aggregate = tightening of plug
Describe the first step of the blood clotting process
- Damage to blood vessel wall = contraction of smooth muscle fibres (vascular spasm)
- Activation of sympathetic nervous system = further vasoconstriction
- Endothelial cells release specific chemical factors and local hormones
- Endothelial cells become sticky to platelets
Describe the third step of the blood clotting process
- Fibrin (protein in plasma), for blood clotting
- Formation of fibrin clot requires reactions called coagulation cascade
Describe the components of Plasma
- About 55-75% of blood is plasma
- 92% water, 8% other substances
List the functions of plasma proteins
- Transport substances bound by plasma proteins
- Maintain normal blood pressure by contributing to viscosity
List three plasma proteins
- Albumin
- Globulins
- Fibrinogen
Describe the role of Albumin
- ~60% of plasma proteins
- Regulates blood osmotic pressure
- Binds reversibly & transports main chemicals in blood
Describe the role of Fibrinogens
- Produced by the liver
- Essential for clotting process