CV system Part 2 Flashcards
functions of blood
- transport: blood gases, nutrients, wastes, processed molecules, regulatory molecules
- regulation: pH, osmosis, body temp
- protection against foreign substances: antibody production
- clot formation: repair damaged tissues, stops clot formation
regulation as a function of blood
pH of blood is kept b/w 7.35 and 7.45
- osmosis: maintenance of fluid balance
- body temperature regulation with vasodilation and constriction
composition of blood
blood consists of 8% if our total body weight (4-6 L in adults)
- plasma: 55%
- formed elements: 45%
- buffy coat: layer when centrifuged composed of platelets and WBC
bicarbonate system
works as a buffer to avoid any large changes in blood pH
- also a way of carrying CO2 in our blood
blood plasma
the fluid portion that makes up 55% of our blood
7% proteins
91.5% water
1.5% other solutes
formed elements (blood)
45% of our blood
- includes platelets, WBC and mostly RBC
describe blood as a connective tissue
extracellular matrix: plasma
cellular component: formed elements
colloid
a fluid that contains suspended substances
- water, proteins, ions, nutrients, waste products, gases, regulatory substances
proteins present: albumins, globulins, fibrinogens
albumins
a protein present in plasma
- most abundant (58%)
- fairly small protein, doesn’t leave blood supply or pass into tissues therefore keeps concentration gradient regular (fluid comes into blood to keep it from becoming too concentrated)
- transports FAs, bilirubin and thyroid hormones
globulins
a protein present in plasma
- 38% of plasma proteins
- antibodies, transport lipids (cholesterol), iron, sex hormones (also cholesterol based)
- there are alpha, beta and gamma types
fibrinogen
a protein present in plasma
- 4% of plasma proteins
- important in blood clotting
components of formed elements
RBCs: erythrocytes
WBCs: leukocytes
platelets: thrombocytes
red blood cells
aka erythrocytes - make up 95% of formed elements
- biconcave discs with no nucleus, mitochondria or organelles
- contain hemoglobin which transports O2 and CO2
- converts CO2 and H2O into carbonic acid (H2CO3)
white blood cells
aka leukocytes - makes up 5% of formed elements
- 2 types: granulocytes and agranulocytes
granulocytes
one type of WBC
have large granules and have multi-lobed nuclei
3 types:
- neutrophils, eosinophils, basophils
agranulocytes
one type of WBC
have small granules and nuclei are not lobed
2 types:
- lymphocytes and monocytes
platelets
aka thrombocytes
- cell fragments that form platelet plugs and release chemicals necessary for blood clotting that signal neighbouring cells to come help
hematopoiesis/ hemopoiesis
the process of blood cell production
- when occurring post-birth, happens in red bone marrow and lymphatic system
stem cells
all formed elements are derived from a single population (hemocytoblast) found in red bone marrow
- basically differentiate into different types of formed elements
proerythroblasts
become red blood cells
reticulocyte
immature RBC that has no nucleus or organelles
- when released into blood, it takes 2 days to become a RBC
myeloblasts
differentiate into the granulocytes: basophils, neutrophils and eosinophils
lymphoblasts
become lymphocytes
monoblasts
become monocytes
megakaryoblasts
parts break off and cell fragments are known as platelets
amount of red blood cells found in adult woman and adult male
men: 5.4 million/uL
women: 4.7 million/uL
shape of RBC
8um diameter, biconcave disc that creates more surface area for gas exchange to occur
components of a RBC
- one third hemoglobin
- two thirds lipids, ATP and carbonic anhydrase
what do RBC transport
- oxygen: 98.5% is bound to Hb
- carbon dioxide: 23% is bound to Hb, 7% dissolved in plasma and 70% dissolved as bicarbonate
- hydrogen ions: generated by carbonic anhydrase reaction, also play a role in altering pH changes
hemoglobin
composed of:
- 4 globin molecules
- 4 heme molecules that each contain 1 iron atom which transports O2 and CO2 (carbonic anhydrase is involved)
- CO2 bind to globin and O2 binds to iron
3 states of hemoglobin
- oxyhemoglobin
- deoxyhemoglobin
- carbaminohemoglobin
oxyhemoglobin
transporting oxygen
- can be bound to alpha or beta globins
deoxyhemoglobin
has no oxygen bound
- does’t usually happen, but could during intense exercise
carbaminohemoglobin
is transporting CO2
erythropoiesis
RBC production, takes about 4 days
- 2 million RBCs are degraded per second but 25 trillion are in circulation
- and RBC lasts for 120 days in circulation: they can’t repair themselves once damaged because they have no organelles
erythropoietin
a hormone produced by the kidney that stimulates RBC production when blood O2 levels are low
- released based on oxygen delivery to the kidney
RBC recycling
- natural degeneration of RBCs: death and phagocytosis by macrophages in spleen, liver or red bone marrow
- separation of components
- globin protein: amino acids get recycled
- heme: iron is removed and recycled in the liver, spleen and red bone marrow ; heme is then transported through blood on transferrin (a carrying protein)
- iron-free heme: converted into bilirubin which creates colour in bile, urine and feces
function of WBCs
- protect body against microorganisms and remove dead cells and debris
- nucleated, no hemoglobin so not involved in transport of O2
- have different types of movements
types of WBC movements
3 types:
- ameboid movement
- diapedesis (emigration)
- chemotaxis
ameboid movement
- plasma membrane of WBC creates armlike projections that grab out and extend to digest things
diapedesis
aka emigration
- cells become thin and elongate and either move between or through endothelial cells of capillaries
- WBC leave CV system and enter into tissues surrounding blood supply
chemotaxis
- attraction to and movement toward foreign materials (which release chemicals that attract WBC) or damaged cells
- phagocytize bacteria and die off: this accumulation of WBC is pus