A&P 2 Exam 1 - Blood + Heart

what is blood **

• it is a specialised form of liquid/fluid CT

• CT means this tissue has cells, some fluids, some fibers (collagen + elastin fibers) in it!

• blood has 2 parts:

• —> plasma: the liquid part of blood which has water, electrolytes, proteins

• —> formed elements: cells within the plasma (the liquid part of blood)

• ——> 3 types of cells that make up formed elements in plasma: erythrocytes (RBCs), leukocytes (WBCs), platelets

microscopic slide of blood cells

• monocyte, neutrophil, lymphocyte is WBC

blood composition

• you will see 3 things after centrifugation:

• 55% straw coloured fluid on top: plasma

• less than 1% is middle = buffy coat: WBCs/leukocytes + platelets

• 45% bottom = erythrocytes (RBCs)

what is the most dense part of blood

red blood cells/erythrocytes

they settle at the bottom cuz they are viscous + heavy

*** WHAT IS HEMATOCRIT

• the percentage of red blood cells in any volume of the blood

• —→ males have higher hematocrit than females cuz females bleed every month so lose small amount of blood every month

• males: 47% ± 5%

• females: 42% ± 5%

physical characteristics of blood

• blood is sticky, opaque fluid with slightly metallic taste

• if blood has high O2, is scarlet

• if blood has low O2, is dark red

• pH of blood if lvls of acids + bases are balanced: 7.35-7.45 **

• blood makes up around 8% of body weight

• average volume: males have 5-6L; females have 4-5L

transport functions of blood **

• blood is most important tissue in the body

• every good or bad thing is dissolved in blood + is carried to its final destination

• transport:

• carries oxygen + CO2 +nutrients + delivers O2 + nutrients to body cells

• transporting metabolic wastes to lungs + kidneys for elimination

• all endocrine hormones are (transported) in the blood + carried to their final destination (target organs)

regulation functions of blood

• blood is maintaining the normal pH of the body

• blood maintains the level of electrolytes in the body

• blood maintains water + electrolyte balance of the body

• (maintains body temp by absorb + distribute heat)

red blood cells carry what + resp for what

oxygen

→ they are resp for transporting gases

white blood cells responsible for what

fighting infections

protection funcs of blood

• white blood cells in blood play an important role in fighting against infections

• platelets in blood helps in clotting/stopping the blood

plasma of the blood

• is straw-colored sticky liquid/fluid part of the blood

• 90% of plasma is water; WATER IS MOST IMP/ABUNDANT COMPONENT OF PLASMA

• other things present in plasma: some hormones, some electrolytes, some gases, globulins, fibrinogen, MOST IMPORTANT: PLASMA PROTEINS

• —> all plasma proteins made by liver

• plasma proteins remain in the blood; never taken up by cells

• MOST ABUNDANT PLASMA PROT IS ALBUMIN; MAKES UP 60% OF PLASMA PROTS in plasma

albumin in blood func

• albumin is the most abundant plasma prot; makes up 60% of plasma prot in plasma of blood

• FUNC: KEEPS/HOLDS WATER WITHIN THE BLOOD VESSELS BY A FORCE CALLED OSMOTIC (PRESSURE OR) FORCE/HYDROSTATIC FORCE

• - albumin exerts force on water

fibrinogen **

• a plasma protein in plasma of blood

• func: is an inactive protein that must be converted into its active form called fibrin

• fibrin is then going to help platelets to clot/stop the blood

what are blood vessels

• hoses/pipes in which blood is running

• - arteries, veins, capillaries

formed elements

• 3 types: are RBCs, WBCs, platelets

• WBC IS THE ONLY CELL OUT OF THE FORMED ELEMENTS WHICH IS COMPLETE CUZ HAS A PLASMA MEMB, NUCLEUS, CYTOPLASM (all 3 parts of a cell)

• RBCs dont have a nucleus or organelles so are not considered as complete cells

• platelets are cell fragments; so are not complete cells

• most blood cells are made by bone marrow + stay in blood for certain period of time then they are taken away

RBCs/erythrocytes

most important function of RBCs: TRANSPORT GASES (oxygen + CO2)

• RBCs only have a wall

• are biconcave disc shaped cells with no nucleus, no organelles

• —> cuz we want RBCs to be filled up with a pigment called hemoglobin for gas transport

• —> biconcave disc shape especially helps RBCs to hold more hemoglobin

• —> RBC has no nucleus or organelles so hemoglobin can take the space of the nucleus and the space of the organelles

• —> RBC has no mitochondria

• —> hemoglobin is a pigment in RBCs responsible for holding oxygen

• RBCs can change their shape(inc/dec in size) when they pass thru blood vessels cuz they have special prot in plasma memb called spectrin

—> how RBCs change their shape depend upon whr they are passing thru

hemoglobin structure (DRAW it)

1 hemoglobin (pigment) has

4 globin chain

4 centrally placed hemes

4 iron (ferrous)

4 O2 (cuz each iron holds 1 O2)

hematopoiesis **

• is FORMATION OF ALL BLOOD CELLS

• most of red blood cells made in bone marrow, which is present in medullary cavity + spongy part of bone!

hemopoietic stem cell **

• every cell in body is made by a mother cell

• HEMOPOIETIC STEM CELL/hemocytoblast = the mother stem cell that gives rise to all blood cells (formed elements) in the body

• need certain type of hormones, vitamins, and food in diet to make what blood cells body wants

• —> stem cell = undifferentiated cell that will start making whatever body wants if they have what they need

erythropoiesis **

• (process of) formation of RBCs that takes about 15 days

• —>we must give hemopoietic stem cell/ hemocytoblast (the mother cell) what they need (some hormones + some chemicals + some food + vits) then it will start making you RBC

• when hemopoietic stem cell commits to making RBCs, it will change its name to PROERYTHROBLAST

• - proerythroblast will past thru all the stages + within 15 days, it will become a mature erythrocyte (RBC)

regulation and requirements of erythropoiesis

• we want a balance of RBC

• we do not want too much RBC cuz RBC is thick + viscous so they can clot + slow down movement

• we dont want too little RBC cuz they wont be able to carry enough gases around body

3 important things we need to make RBC **

• MOST IMPORTANT IN FOOD (DIETARY): folic acid/iron, vitamin B12

• HORMONE RESPONSIBLE FOR MAKING RBC = ERYTHROPOIETIN

• erythropoietin produced by the kidney

• —> kidney produces erythropoietin when we have low levels of oxygen (hypoxia) due to any reason e.g. not enough RBC/oxygen

• MOST IMP STIMULUS FOR KIDNEY MAKING ERYTHROPOIETIN: HYPOXIA (low oxygen)

• —> hypoxia is a signal to the kidney when our levels of RBC/oxygen is low due to any reason

• —→ erythropoietin will then enter the blood + act on the bone marrow + it will tell your bone marrow to make red blood cells

causes of hypoxia (low oxygen)

• decreased number of RBCs (due to hemorrhage/inc destruct) - if no RBCs, we cant carry oxygen!

• low levels of / not enough hemoglobin in your RBCs! (e.g. iron deficiency)

• people living in higher altitudes have reduced availability of O2, leading to hypoxia

• —> these 3 stress factors will lead your kidneys to start releasing erythropoietin

• —> erythropoietin acts on bone marrow and bone marrow will start making RBCs

if you do not have good amount of iron/folic acid or vit B12 deficiency…

RBC levels will fall

what is the part in the hemoglobin which holds O2? **

iron/ferrous