Transport In Humans

Question 1

What are the 4 main components of blood

Answer 1

Plasma
Red blood cell
White blood cell
Platelets

Question 2

What does Plasma contain

Answer 2

Contains mainly water & substances such as glucose, salts, proteins, amino acids, fats, vitamins, hormones & metabolic waste products such as urea.
Also contains red & white blood cells

Question 3

Function of plasma

Answer 3

Plasma transports;
-blood cells around the body
-nutrients from small intestine to other parts of the body
-metabolic waste products from organs where they are produced to organs such as the kidney & lungs for removal
-hormones from endocrine glands to target organs to excretory organs for removal

Question 4

Function of platelets

Answer 4

Prevent excessive blood loss & the entry of harmful organisms into the bloodstream.
Platelets Contains An enzyme that catalyses the conversion of soluble protein fibrinogen to insoluble fibrin threads. The fibrin threads form a network that entangles red blood cells to form a clot.

Question 5

Features of red blood cells

Answer 5

-circular, biconcave in shape
-no nucleus
-it’s cytoplasm contains a red pigment called haemoglobin
-are flexible

Question 6

Function of red blood cells

Answer 6

Transport oxygen from lungs to other parts of the body

Question 7

How did the Red blood cell adapt to perform its function?

Answer 7

Contains haemoglobin that can bind reversibly with oxygen. In lungs where oxygen levels are high, haemoglobin binds with oxygen to form oxyhemoglobin. When oxygen concentration is low, oxyhemoglobin releases its oxygen to tissue cells.

Biconcave shape to increase surface area to volume ratio which increases rate of absorption & release of oxygen.

Flexible & can change into a bell shaped structure so that they can flow easily through narrow blood capillaries. (One cell thick)

No nucleus, which means that there is more space for haemoglobin to bind with more oxygen/to be stored.

Question 8

What are the 2 main white blood cells

Answer 8

Phagocytes
Lymphocytes

Question 9

Phagocytosis

Answer 9

Is a process by which a white blood cell engulfs & destroys foreign particles such as bacteria

Question 10

Function of white blood cells

Answer 10

To perform phagocytosis

Question 11

What does Lymphocytes do?

Answer 11

Produce antibodies that:
- recognise foreign particles
- destroy disease causing organisms such as bacteria & viruses.
- cause bacteria to clump together for easy ingestion by phagocytes.
-neutralise toxins produced by bacteria
-recognise and destroy phathogens

Question 12

What happens after organ transplant & tissue rejection

Answer 12

After transplant, the recipients white blood cells may respond by producing antibodies to destroy the transplanted organ

Question 13

The heart

Answer 13

A muscular pump that Keeps blood circulating throughout the body.

Question 14

Arteries

Answer 14

Carry oxygenated blood away from the heart

Question 15

Arterioles

Answer 15

Artistes branch out to form tiny vessels called arterioles

Question 16

Blood capillaries

Answer 16

Arteriols divide even further to form capillaries.
Microscopic blood vessels
Found between cells of almost all tissues
One cell thick
Walls are partially permeable, enables certain substances to diffuse quickly through them.
Numerous branches provides a large surface area (lowers blood pressure) for exchange of substances between blood & tissue cells )slow to give more time)

Question 17

Venues

Answer 17

Before capillaries leave organ/tissue, they unite to form small vessels called venues

Question 18

Veins

Answer 18

Venues join to form bigger veins.
Veins carry deoxygenated blood back to the heart

Question 19

Blood pressure & speed of blood flow of arteries

Answer 19

Arteries need to be able to withstand the high pressure of the blood forced out of the heart. Blood that flows in the arteries is fast moving

Question 20

How are the arteries adapted to perform its function?

Answer 20

Arteries have thick, muscular & elastic walls
This enables artery to withstand the high blood pressure as blood is forced out of the heart.
They make the artery wall elastic, enabling its wall to stretch & recoil or spring back.
This helps to push the blood in spurts along the artery & also give rise to the pulse.

Question 21

Blood pressure & speed of blood flow in veins

Answer 21

The blood pressure in veins are much lower than blood pressure in arteries. Blood flows more slowly & smoothly in the veins

Question 22

How are the veins adapted to perform its function?

Answer 22

The walls of the veins need not be as thick or muscular as those arteries of about the same size.
Veins also contain less elastic tissue. Instead, most veins have internal valves along their length to prevent back flow of blood.

Question 23

Arita

Answer 23

2 upper chambers
Receives blood from veins
Comparatively thin muscular walls, since they only force blood into the ventricles that lie directly below them. (Does not require pressure)

Question 24

Why is the muscular wall on left side of the heart thicker?

Answer 24

As the left side needs to pump to the whole body while the right side pumps to lung only

Question 25

Ventricles

Answer 25

2 larger, lower chambers.
Comparatively thick muscular walls.
Left ventricle is much thicker because it pumps blood around the whole body & this requires high pressure.
Right is thinner since it only pumps blood to the lungs. (Close to the heart)

Question 26

Median septum

Answer 26

Muscular wall that separates right & left sides of the heart.
Runs down the middle of the heart.
Prevents mixing of deoxygenated blood with the oxygenated blood, which will reduce the amount of oxygen carried to the rest of the body.

Question 27

Tricuspid valve

Answer 27

Prevents back flow of blood from right ventricle to right atrium

Question 28

Bicuspid valve

Answer 28

Prevents back flow of blood from left ventricle to left atrium

Question 29

Aortic valve (semi-lunar valve in aroma)

Answer 29

Prevents back flow of blood from aorta to left ventricle

Question 30

Pulmonary valve (semi-lunar valve in the pulmonary artery)

Answer 30

Prevents back flow of blood from pulmonary artery to right ventricle

Question 31

Upper vena cava transports…

Answer 31

Blood from the head, neck & forearms back to the heart

Question 32

The lower vena cava transports…

Answer 32

Blood from rest of the body back to the heart

Question 33

Coronary arteries

Answer 33

Bring oxygen & nutrients to the muscles in the walls of the heart

Question 34

What happens when there is a hole in the heart?

Answer 34

Blood flows from left to right side of the heart (due to pressure difference)
Causes less oxygen to be transported to body cells for respiration.
Patients with this condition may suffer from;
Shortness of breath, fatigue.
In more serious cases, medical treatment / surgery may be required

Question 35

When ventricular muscle relaxes…

Answer 35

Fall in pressure causes semi-lunar valves to close to prevent back flow of blood.
Bicuspid & tricuspid valves open & blood flows from Arita to ventricles

Question 36

When ventricular muscles contract,

Answer 36

Causes rise in pressure.
Causes bicuspid & tricuspid valve to close to prevent back flow of blood into atria

Question 37

The pulse

Answer 37

Produced after every ventricular contraction as the heart pumps blood

Question 38

What are the main arteries of the body?

Answer 38

Arteries leaving the heart:
-pulmonary artery
-Aorta
From the aorta, the following arteries arise:
-Arteries to the head, neck & forearms
-the hepatic artery
-artery to stomach & intestines
-the renal artery

Question 39

What are the main veins of the body?

Answer 39

Blood is returned to the heart by:
-pulmonary vein
-superior & inferior Vena cava

Inferrior vena cava receives blood from:
-renal vein
-hepatic vein

Question 40

The hepatic portal vein

Answer 40

The veins from the small intestine do not open directly into the inferior vena cava.
Instead, they unite to form the hepatic portal vein which enters the liver & branches into numerous capillaries.
Carries blood from one capillary network to another.
Thus, the hepatic portal vein arises from capillaries in the wall of the small intestines at one end & give rise to capillaries in the liver at the other end.

Question 41

What happens during a heart attack?

Answer 41

During a heart attack, blood flow to a particular part of the heart is completely blocked.
Due to the blocked blood flow, that part of the heart does not receive sufficient oxygen & nutrients.
That region of the heart dies. Extensive heart damage is often fatal as the heart is no longer able to pump blood to the various parts of the body.

Question 42

What are the causes of coronary heart disease?

Answer 42

Fatty substances such as cholesterol & saturated fats may be deposited on the inner surface of the coronary arteries .
This narrows the lumen of these arteries & increases blood pressure. Such an affected artery develops the risk of a blood clot being trapped in the artery. If it occurs in the coronary arteries, the supply of blood & oxygen to the heart may be completely cut off.
Oxygen is needed for aerobic respiration to release energy for the activities of the muscle cells. Without oxygen, the heart muscle cells may be damaged, & heart attack occurs.

Question 43

What are the risk factors of heart disease?

Answer 43

1. Smoking
   Contains carbon monoxide & nicotine which increases risk of heart attack
2. Unhealthy diet
   A diet high in cholesterol, saturated fats & salt content increases the risk of high blood pressure & heart attack.
3. Genetic factors
   High blood pressure/cholesterol Can run in the family (family history)
4. Age
   Risk of heart attack increases as age increases
5. Sedentary lifestyle
   Lack of exercise & being inactive leads to the build up of fatty deposits that block the arteries

Question 44

What can we do to reduce the risk of getting coronary heart disease?

Answer 44

1. Have a healthy diet
   Animal fats should be substituted with polyunsaturated plant fats which do not stick on the inner surface of the arteries.
2. Don’t smoke
3. Regular physical exercise has long-term beneficial effects on the circulatory system.
   Strengthens & maintains the elasticity of the arterial walls.

Question 45

state what happens if there is a blockage at the coronary arteries

Answer 45

the heart muscles will be deprived of oxygen & glucose. a prolonged lack of oxygen & glucose decreases the rate of respiration of heart muscle cells in the heart muscles & will slow down or stop. this could lead to a heart attack.