Gas exchange in humans

Plan of breathing system

Gas exchange in Air sacs adaption

One cell thick wall of air sacs and capillaries(short diffusion distance )

Large no of air sacs (up surface area for diffusion)

Present of water film (oxygen dissolve in water film so gas diffusion occur effectively

And richly supplied with blood capillaries (maintain steep concentration gradient of gases between air sacs and blood

Process of air sacs

Oxygen dissolved in water film-Diffuse to blood through wall of air sacs and capillaries-combine with haemoglobin in rbc co2 diffuse in opposite direction

Transport of oxygen

Carried by red blood cell combine with haemoglobin to form oxyhaemoglobin(

(Low oxygen in body cell and high in airs sacs

Transport of carbon dioxide

Transport in form of hydrogen carbonate ions in plasma

Most enter red blood cell and diffuses out into plasma and carries to lungs

(High co2 in body cell and low in air sacs

Red blood cell properties

Bioncave shape to shorten diffusion distance of oxygen in and out of haemoglobin in rbc and increase surface area

No nucleus to carry more haemoglobin

Inhalation and exhalation

Diaphragm muscles contact diaphragm contract

Intercostal muscles contract

Rib cage moves upwards and outwards

Volumes of lungs increase

Air pressure in lung lower than atmospheric pressure

Air flow into lung

Vice versa in exhalation

Circulatory system

Consists of heart blood and blood vessels(artery capillary and vein) double circulation mean blood go through heart twice in one complete circulation

Septum valve left side and right side

Prevent mixing of oxygenated and deoxygenated blood

Prevent back flow of blood from ventricles into atria when ventricles contact

Left is oxygenated right is deoxygenated

Four chamber of heart

Left atrium ,left ventricles ,right atrium and right ventricle

Main function of heart

Pump blood though body and deliver oxygen and nutrients to tissue and remove carbon dioxide and waste

Role of atrium

Atrium receive blood from right atrium(vena cava)deoxygenated blood and left atrium from lungs oxygenated blood (pulmonary vein)

Role of ventricles

Pump blood out of heart-right ventricles to lungs(pulmonary artery ) and left ventricles to body (aorta)

Why Left ventricles thicker than right ventricles

pump blood at higher pressure into aorta to supply entire body

4 main blood vessels connect to heart

Aorta ,pulmonary artery (from heart to other part),pulmonary vein(from body to heart ) , vena cava

What control heartbeat

Sa node ,initiate electrical impulses to regulate heartbeat

Pulmonary artery

From body to heart

From heart to body high blood pressure force by pumping action of heart smaller lumen and thick wall to withstand high blood pressure

low blood pressure force by the contraction of surrounding skeletal muscles large lumen so blood can flow to heart easily

Thin wall and valves are present to prevent back flow of blood

Lymphatic system(protect against infections)

Consist of lymph vessel (for lymph capillaries)and lymph nodes(formed by wbc when lymph nodes kills pathogens

Capillaries function

Allow exchange of material between blood and body cell

Rbc wbc and platelets function

Carry oxygen

Kill pathogens.

Cause blood clotting

Tissue fluid function

Is blood without rbc and blood platelets and plasma protein

Deliver substance and remove waste from body cell

Where does change of material take place

In dense network of cappillares

Formation of tissue fluid

1.when blood reach arterial end, high hydrostatic pressure by pumping action of heart forces all nutrients except plasma protein rbc out like (oxygen water) though capillary wall

At venous end most tissue fluid is back into capillaries by osmosis water potential of tissue fluid is higher than blood

Blood pressure at venous end is low

The rest of tissue fluid is forced into lymphatic capillaries forming lymph

Importance of lymphatic system

Transport fat and vitamins from lacteal to blood