transport in humans

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components of blood

(1) Plasma

- pale yellowish + 90% water

functions : transport nutrients ( glucose ) , metabolic waste ( urea ) to kidney , hormones ( glands to organs ) , carbon dioxide

contains soluble protein like fibrinogen

maintain body temp ( distribute heat )

(2) Red blood cells

- transport oxygen from lungs ---> body

- needed for respiration ---> produce energy

STRUCTURE!!

> circular and biconcave - increase SA : VR for efficient diffusion of oxygen

> contains haemoglobin - binds to oxygen reversibly ---> oxyhaemoglobin

> no nucleus - more space to store haemoglobin ---> more oxygen

* when O2 bind w haemoglobin ---> oxygenated ( red )

* when O2 release from haemoglobin ---> deoxygenated ( purplish-blue )

(3) White blood cells

- colourless , no haemoglobin , irregular in shape , have nucleus

>Phagocytes ( lobed nucleus and granular cytoplasm )

- ingest foreign particles

- protect body from bacteria

- phagocytosis - ( process ) ingesting foreign particles such bacteria ----> so that body X harm

>Lymphocytes ( spherical and no granular cytoplasm )

- produce antibodies against microorganisms

- destroy pathogens , assist phagocytes to clump bacteria

- produce antitoxins to neutralize toxin

(4) Platelets

- contain thrombokinase ( enzyme )

- function : clot blood - prevents blood loss and entrance of bacteria

PROCESS !!

-platelets ( activated ) ---> release thrombokinase

-tgt with calcium ions convert prothrombin ---> thrombin

-thrombin converts soluble fibrinogen ---> fibrin

-forms mesh and trap red blood cells

-cells clump together to form clot to seal wound

organ transplants

- lymphocytes may respond by producing antibodies to destroy the transplanted organ ( tissue rejection )

donor close to recipient

weaken immune system to prevent rejection

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(5) blood groups

consider : recipient ( antibodies ) ; donor ( antigens )

blood type A - antibody B and antigens A

blood type B - antibody A and antigens B

blood type AB - no antibody and has both A and B antigens

blood type O - has both antibodies A and B and no antigens

* agglutination of red blood cells will occur if B donates to A *

IMPT QUESTION !!

- explain why blood type O is considered a universal donor and blood type AB is considered a universal receiver

for blood type O , it has no antigens for antibodies to react and agglutinate with

for blood type AB , it has no antibodies to react with antigens so agglutination X

(6) blood vessels

> arteries

carry blood away from heart

transport oxygenated blood

thick muscular walls to withstand high pressure

small lumen to maintain high pressure --> fast flow of blood

> veins

carry blood to heart

transport deoxygenated blood

thin walls and less elastic walls ( low pressure )

large lumen ( low pressure , slow flow of blood )

** valves prevent back flow of blood acts as a barrier , assisted by contraction of skeletal muscles **

valves open - contracts , valves close - relax

> capillaries

allows xchange of materials between blood and tissue

arteries ----- veins

one cell thick

partially permeable , branched network

(7) heart

- four chambers

> atrium ( atria ) - thinner walls , receive blood ( l.p ) , force blood into ventricle

> right ventricle - pumps blood short list to lungs

> left ventricle - thicker muscular walls to withstand high pressure as it needs to pump blood to the rest of the body

> median septum - separates oxygenated and deoxygenated blood , ^ efficiency of circulatory system

** double circulation**

- pulmonary ( lungs )

lower pressure , slower

- systemic ( body )

high pressure , faster

(8) cardiac cycle

a lub sound is produced when the valves close

contraction of ventricles - ventricular systole

a dub is produced when valves close

relaxation of ventricles - ventricular diastole

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cardiac cycle !!

step 1 : both atria and ventricles relax

A filled w blood

after that it contracts when it forces the blood into V

step 2 : ventricles contracts , atria relaxes

T and B valves close to prevent back flow of blood

ventricle contracts : ventricular systole

step 3 : semi lunar valves open

oxygenated blood enter from right V enter pulmonary artery ---> aorta

step 4 : ventricle relaxes , semi lunar valves close to prevent back flow of blood

"dub" sound when S.I closes

ventricle relaxes : ventricular diastole

step 5 : decrease in V pressure , T and B valves open allow blood enter V

pressure in heart !!

ventricular contraction in A forcing blood into V

left ventricle contracts , bicuspid valve close P ^

left ventricle P higher than aorta S.I valves open

left ventricle relax , ( what valves do ? ) then P decrease

when the P is lower than aorta the bicuspid valve open

then it increase again when blood enter atrium

coronary heart disease

> coronary artery - supply oxygen and nutrients to the heart ---> heart attack if artery blocked

CAUSES -- excess cholesterol and fats ----> deposits ---> atherosclerosis

lumen narrow , P ^ and blood clot form block blood flow ---> thrombosis

smoking and emotional stress

exercise regularly and have proper diet

deoxygenated blood enter the vena cava and into the right atrium . the tricuspid valves open and blood enter the right ventricle.

the semi lunar valves open and blood enter the pulmonary arch and to the pulmonary artery

oxygenated blood enter pulmonary vein and into the left atrium . the bicuspid valves open and blood enter the left ventricle

semi lunar valves open and blood enter the aorta and the blood to the body