chapter 7 Flashcards
components of circulatory system
heart, blood vessels, blood❤️
functions of blood (8)
- transport nutrients and oxygen to cell
- transport co2 and wastes away from cell
- transport hormones to cells
- regulate pH
- thermoregulation
- protect against disease (WBC)🦠
- clotting to prevent blood loss
- maintain water and ion content in bodily fluids 💦
components of blood
liquid: palms 55%
non-liquid: formed elements 45% (cells and cell fragments)
erythrocytes
RBC
suited for o2 and co2 transport
have HGB (protein) and has no nucleus to make room for it ( when combine with o2, HGB is red)
large SA to V to speed up gas exchange
made in bone marrow, destroyed in liver/spleen by macrophages (120 days)😩
small, 8um and flexible to go through narrow capillaries
leucocytes
fight infections/provide immune responses
granulocytes: granular cytoplasm, lobed nucleus
agranular: lymphocytes and monocytes
macrophage is type of monocyte- phagocytic
few minutes to YEARS!!
get rid of dead or injured cells 😭(RIP) and invading microorganisms 🦠
thrombocytes
small cell fragments with no nucleus😔
1/3 of RBC🖕👌
made in bone marrow life span of a week
important in coagulation
plasma
91% water
rest is dissolved substances
glucose, AA, ions, wastes (urea: waste of protein metabolism), gases
oxygen transport x2
3% dissolved in plasma
97% carried in HGB to make oxyhemoglobin
this bond is v loose to breaks down easily to release oxygen
when o2 conc is high (capillaries in lungs), o2 combines with HGB easily
when o2 conc is low (cells) oxyhemoglobin breaks down
Oxygenated
lots of oxyhemoglobin
Deoxygenated
only haemoglobin
co2 transport x3
8% dissolved in blood plasma
22% combines with HGB to form carbaminohaemoglobin
70% carried in plasma as bicarbonate ions (HCO3-) (H+)
co2 diffuse into plasma because of con grad, most of it reacts with water to from carbonic acid. this then dissociates into hydrogen ions and bicarbonate ions
in lungs:
8% diffuses out
22% breakdown then diffuse
70% ions recombine to carbonic acid then breaks down by enzymes to water and co2, then diffusion
how are nutrients and waste transported
all dissolved in blood plasm
inorganic: ions
low thrombocytes=
low erythrocytes=
high leucocytes=
Haemophilia
Anaemia
Infection
arteries
carry blood away from the heart
carry oxygenated blood
have thick, smooth, muscular walls with elastic fibres
no valves
high pressure blood because it is closer the heart, increase as ventricles contact
further down in skin because it contains high pressure blood
veins
carry blood toward the heart
carry deoxygenated blood
thin, relatively inelastic (pressure is constant) walls with little muscle
have valves
blood is under low pressure because most of the pressure is lost as it flows through the tiny capillaries
Capillaries
Microscopic
connects veins and arteries
network
1 cell thick: thin for easy diffusion of nutrients and wastes
arterioles (vaso)
smooth muscle and elastic fibres (stretch and recoil)
Vasoconstriction: contraction to reduce the lume (inside space) size/diameter of artery to reduce blood flow to an area. reduce loss of body heat in cold temperatures, arteries constrict to let less blood go to the skin and more in the core region.
vasodilation: relaxing to increase lumen size, increase blood flow to an organ.In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation . This allows more heat to be lost from the blood.
adrenaline causes vasoconstriction in most arterioles, but vasodilation in skeletal/cardiac muscle
cardiac cycle
sequence of events that occur in one heart beat
systole and diastole
systole: when heart muscles contract, pumping
diastole: when heart muscles relax, filling
artrial systole/ventricular diastole: atria contracts forcing blood into ventricles
ventricular systole/ atrial dyastole: atria relax and refill while ventricles contact which forces blood into arteries
cardiac output
=stroke volume x heart beat
stoke volume= volume of blood forced from a ventricle each contraction
cardiac output= amount of blood leaving leaving a ventricle every minute
sinoatrial node
collection of nerve cells in the wall of the right atrium
pacemaker
starts each cardiac cycle by sending nervous impulses which cause the atria walls to contracts, nerve impulses reach the atrioventricular node causing ventricles to contract-> frequency of this is called heart rate
Vasodilation and exercise
when you exercise, large increase in blood flow Is needed to supply oxygen and nutrients and remove carbon dioxide and heat
vasodilation of blood vessels in muscles and contraction to blood vessels
started by anticipatory response from nervous system
continued because wastes (CO2, lactic acid, heat) all act as vasodilators
pulmonary circulation
systematic circulation
blood going to lungs and back to heart
blood going to there parts of the body and back
as blood asses through heart twice ->double circulation
antigen
protein molecules of the surface of erythrocytes that determine blood type
capable of stimulating formation of antibodies
antibodies
molecules in plasm that remove foreign bodies (pathogens)
leucocytes then engulf and destroy inactivated pathogens
specific to each pathogen
Rhesus factor
a further antigen on erythrocyte surface
rh- doesn’t have antigen and makes antibodies that destroy the Rhesus factor
rh+ person has the antigen that makes no antibodies that destroy the Rhesus factor
if the wrong blood type is given…
antibodies in plasma combine with antigens on the surface of foreign blood Agglutination occurs (clumping of cells)
types of blood transfusions x7
whole blood: blood taken with anti-clotting agent added (eliminates disease risk)
Autologous: patienst own blood used that was collected before surgery
red cell concentrate: blood centrifuged and only erythrocytes taken (anaemic/heart disease)
plamsa: used to provide extra clotting factors in severe bleeding and liver disease
platelets: when platelets are too low
Cryoprecipitate: plasma frozen and slowly thawed. contains many clotting factors and used for haemophiliacs
Immunoglobulins: group of proteins acting as antibodies extracted from blood of people that are immune to a particular disease.
blood clotting and defence
- injury to lining of a blood vessels expose collagen fibres to the blood. platelets stick to the collagen fibres.
- platelets releases chemicals that make the surrounding platelets sticky
- platelets clump together. they form an emergency protection against blood loss
- a fibrin cloth reinforces the seal. the clot traps blood cells and eventually dries to form a scab, acts as a mechanical barrier to the entry of pathogens.
after clot is formed, clot retraction occurs(threads contract, pulling damaged blood vessel edges together,) as this occurs a fluid called serum is squeezed out. then scab formed
blood coagulates to prevent blood loss from injured tissue.
clotting factors catalyse the conversion of plasma protein to an active enzyme
