Biology Chapter 6, Transport in Humans

What is the fuction of blood?

Blood transports substances around the human body and defends it against diseases.

What is plasma?

Its the fluid component of blood.

What does 6 components does plasma consist of?

Water, Nutrients (glucose, amino acids, fats, vitamins, minerals), Hormones, Waste (urea, carbon dioxide), Plasma proteins (prothrombin, fibrinogen) and Antibodies.

What is the relationship between red blood cell concentration and altitudes?

1. Oxygen concentration decreases at higher altitudes (“thin air”).

2. Reduced concentration gradient between air in lungs and blood → decrease rate of diffusion of oxygen into red blood cells.

3. Body responds by producing more red blood cells.

Name the 2 white blood cells.

Phagocytes and Lymphocytes.

What are the stucture and properties of lymphocytes?

Large spherical nuclei and produce antibodies

What is the function of the antibodies?

Rupture bacterial cell membranes, Neutralise toxins produced by bacteria, Cause agglutination of pathogens.

What are the stucture and properties of phagocytes?

Irregular in shape, able to move in and out of blood capillaries, Lobed nuclei, Performs phagocytosis

What is phagocytis?

To engulf and digest (destroy) foreign particles e.g. bacteria.

What are platelets?

Platelets are fragments of cytoplasm, Involved in the clotting of blood.

What are thromokinase, thrombin and what do they do in the blood clotting process?

Damaged tissues and platelets produces thrombosiskinase. prothrombin with thrombokinase and calcium ions form thrombin. fribinogen with thrombin form insoluble fibrin which entangles blood cells to form a clot. the clot seals the wound and prevents excessive blood loss.

What is tissue rejection and what can be done to prevent it?

Transplanted organs may be treated as foreign by the antibodies of our body. Lymphocytes produce antibodies, Phagocytes performs phagocytosis. To prevent this from happening, testing has to be done to ensure that the tissues match. Donor and recipient needs to be genetically as close as possible.

Which blood groups can blood group A receive from?

A or O

Which blood groups can blood group B receive from?

B or O

Which blood group can blood group O receive from?

O

Which blood groups can blood group AB receive from?

A, B, O, AB

What are antigens?

Special proteins that are found on red blood cell membranes.

What antigen does blood group A have?

Antigen A

What antigen does blood group B have?

B

What antigen does blood group AB have?

A and B

Does blood group O have antigens?

no antigens

Where are antibodies found and what happens with antibodies and the same type of antigens?

Antibodies are found in blood plasma and will bind to the same type of antigen as the antibody.

•E.g. antibody A will bind to antigen A → cause red blood cells to clump / agglutinate

What antibodies do blood group A have?

b

What antibodies do blood group B have?

a

What antibodies do blood group AB have?

no antibodies

What antibodies do blood group O have?

both a and b

What is the function of an artery?

Transport blood away from the heart

What are the structures of the artery and what do they cause?

Thick, muscular and elastic walls

Thick, muscular: withstand high blood pressure from the heart

Elastic: to allow the walls to stretch and recoil to push blood forward

Narrow lumen to maintain a high blood pressure

Absence of semi-lunar valves (except aorta and pulmonary artery)

Whats the funtion of the vein?

Transport blood towards the heart.

What are the structures of the vein and what do they cause?

Thinner, less muscular and less elastic walls (compared to artery)

Blood pressure is lower in the veins

Wider lumen (compared to artery)

Presence of semi-lunar valves: Ensure unidirectional flow of blood and closes to prevent blood from flowing backwards.

How does Blood Flow “Upwards”?

Since the blood pressure in veins are low, how does blood flow “upwards” from the legs to the heart?

1. Constant pumping of the heart, Blood is constantly pushed forward

2. Contraction of skeletal muscles in the legs during movement: Squeeze veins, push blood forward

3. Presence of semi-lunar valves: Closes to prevent blood from flowing backwards

What is the function of the blood capillary?

Exchange of substances between blood and tissue fluid.

What are the structures of the blood capillaries and what do they cause?

1. One-cell thick wall, partially permeable: Decrease diffusion distance, increase rate of diffusion of substances

2. Narrow lumen allows red blood cells to flow in a single file: Allows for maximum efficiency in substance exchange

3. Highly branched to create a dense network: Increase total cross-sectional area → decrease pressure and speed → increase time spent in capillary for exchange

4. Increase surface area to volume ratio for increase rate of exchange of substances

What is tissue fluid?

Fluid that surrounds tissue cells.

Function of tissue fluid?

Transports dissolved substances, e.g. oxygen, CO2, urea, glucose, amino acids, between tissue cells and blood capillaries

How is tissue fluid formed?

Formed from the high blood pressure on the arterial end that forces blood plasma out of capillaries.

What aubstances are unable to pass from blood into tissue fluid?

Large molecules, e.g. RBC, hormones, plasma proteins

What is the funtion of the heart?

The heart pumps blood to the rest of the body. Cardiac muscles in the heart contract and relax to increase pressure so as to enable blood to be pumped through the chambers and the blood vessels.

Funtion of median septum

Separates the oxygenated blood on the left side to the deoxygenated blood on the right side.

Function of vena cava

Vena cava transports deoxygenated blood to the right atrium.

Function of right ventricle

Right ventricle pumps blood into the pulmonary artery.

Function of pulmonary vein

The pulmonary vein transports oxygenated blood to the left atrium.

function of left ventricle

Left ventricle pumps blood into the aorta

Name the 4 different valves and where theyre located

1. Tricuspid valve: Located between right atrium and right ventricle

2. Bicuspid valve: Located between left atrium and left ventricle

3. Pulmonary valve: Located between right ventricle and pulmonary artery

4. Aortic valve: Located between left ventricle and aorta

Why is the left ventricle thicker?

The left ventricular wall is thicker than the right ventricle because it has more muscle tissue. Why?

1. Left ventricle pumps blood to the rest of the body

2. As the blood has to travel over a longer distance, more pressure is needed to pump the blood.

3. Right ventricle pumps blood to the lungs

4. Compared to the distance travelled to rest of the body, the distance travelled by blood to the lungs is shorter

what is the cardiac cycle?

A sequence of events that takes place in 1 heart beat

what is a systole and diastole?

1. Systole is when the atria or ventricles contract

2. Diastole is when the atria or ventricles relax

state the entire cardiac cycle, 1st part

Blood enters the atria from vena cava and pulmonary vein

• Atrial muscles contract (note that both left and right sides works concurrently)

• Blood is pumped into the ventricles, pushing open the bicuspid and tricuspid valves

state the entire cardiac cycle, 2nd part

After a short pause, the ventricle muscles will contract, causing a rise in the blood pressure in the ventricles, while the atrial muscles relax

• This increase in pressure in the ventricles will cause the bicuspid and the tricuspid valves to close to prevent blood from re-entering the atria

• This causes the “first sound” of a heartbeat, known as the “lub” sound

• The contraction of the ventricle muscles will pump blood into the pulmonary artery and the aorta from the ventricles, pushing open the semi-lunar valves in the pulmonary artery and aorta

State the entire cardiac cycle, 3rd part

During the contraction of the ventricle muscles, the atria muscles relaxes, causing pressure in the atria to decrease

• As the pressure is now lower than that in the vena cava and pulmonary vein, blood will fill the atria from the vena cava and the pulmonary vein

• Ventricle muscles will then relax, and this decrease in blood pressure will cause the pulmonary and aortic valve to close as blood to prevent backflow of blood from the pulmonary artery and aorta

• This causes the softer “second sound” of a heartbeat, known as the “dub” sound

• Atrial muscles will contract again, and the whole cycle repeats

What is a pulse and why is it formed?

1. Produced after ventricular systole

2. Caused by sudden rise in blood pressure in arteries

3. Elastic walls of the arteries will stretch (and then recoil to force blood forward), creating a pulse

4. The number of pulse per minute = number of heartbeats per minute

What is coronary heart disease?

1. One of the most common heart disease

2. Caused by the occlusion (blockage) of the coronary arteries of the heart

3. Coronary arteries supply nutrients, e.g.

   glucose and oxygen, to the cardiac muscle cells so they are able to function (contract & relax)

How does the disease occur?

1. Excess saturated fats and cholesterol in the blood deposit on inner walls of coronary arteries (atherosclerosis)

2. Lumen decreases, blood pressure increases

3. Inner walls becomes rough, increasing the chance of blood clot formation

4. Supply of blood to cardiac muscle cells is cut off

5. Less glucose and oxygen supply, less aerobic respiration, less energy release for muscle contraction

6. Cardiac cells damaged → heart attack

Risk Factors of Heart Diseases:

1. Diet high in saturated fats, cholesterol, salt

2. Smoking, Cigarette smoke contains carbon monoxide and nicotine

3. Genetic factors

4. Age

5. Lifestyle

What are some preventive measures?

1. Eat food with less saturated fats

2. Exercise

3. Quit smoking / vaping

4. Proper stress management