chapter 9

Question 1

Describe the circulatory system

Answer 1

A system of blood vessels with a pump and valves to ensure one way flow of blood

Question 2

Describe the single circulation of fish

Answer 2

2 chambers
single circulation
blood goes through heart only once
Inefficient because blood pressure is lost through capillaries in gills

Question 3

Describe double circulation of mammals includ the circulation names

Answer 3

4 chambers
double circulation

Pulmonary circulation:
heart to lungs
low pressure
right side
deoxy blood

Systemic circulation :
heart to rest of body
high pressure
left side
oxygenated blood

Question 4

Describe double circulation

Answer 4

The blood passes the heart twice during one complete circulation

Question 5

State the importance and advantages of double circulation

Answer 5

To separate the oxygenated and deoxygenated blood .
to maintain high blood pressure at systemic circulation > to supply cells with more oxygen and glucose for respiration to make more energy, faster and more frequently

Question 6

State the structures of the heart

Answer 6

Vena Cava ( inferior / superior ) - entering heart [ deoxygenated blood ]
right atrium
tricuspid valve
right ventricle
semilunar valve
Pulmonary artery - away from heart to lungs
Pulmonary veins ( entering heart from lungs )[ oxygenated blood ]
left atrium
bicuspid valve
left atrium
semilunar valve
Aorta ( away from heart )

Septum ( seperates 2 sides of heart )
coronary artery ( inside muscle tissues , supplying oxygen and nutrients to heart )

Question 7

Which sides recieve oxygenated blood and deoxgenated blood

Answer 7

oxygenated : left side
deoxygenated : right side

Question 8

explain the relative thickness of the muscle walls

Answer 8

1. ventricles have thicker muscle walls than atrium >? > ventricles pump blood out of heart so need higher pressure
2. Left ventricle has thicker wall than right ventricle > need higher pressure as its pumping for longer distance

Question 9

What is the function of the septum

Answer 9

to separate the oxygenated and deoxygenated blood and prevent them from mixing

Question 10

Describe the function of the valves

Answer 10

basic function:
prevent blood flowing backwards to ensure blood flow in 1 direction

AV valves:
tricuspid : seperate right atrium and right ventricle
Bicuspid : seperate left atrium and left ventricle

semilunar valves: only artery with valves

Question 11

Describe the movement of the valves and the contractions of the heart

Answer 11

AV valves open when atrium contract, close when ventricles contract

Semilunar : open when ventricle contracts

Question 12

Describe the pathway of blood through the heart

Answer 12

Deoxygenated blood from body tissues flow into right atrium via vena cava

Once the right atrium has filled with blood , the atrium contracts, tricuspid valve opens.

blood is pushed through the tricuspid valve into the right ventricle . The walls of the right ventricle contract, semilunar valve opens.

Blood is pushed into the pulmonary artery to the lungs

The blood travels to the lung and moves through the capillary at the alveoli where gas exchange occurs.

Oxygenated blood returns to the left atrium via the pulmonary vein . Left atrium contracts and bicuspid valve opens

Blood then enters the left ventricle , which contracts and semilunar valve opens.

Blood is pumped through the aorta, to rest of the body tissues

Question 13

State how the activity of the heart is monitered

Answer 13

1. Electrocardiogram
2. Measuring pulse rate
3. listening to the sounds of valves closing using a stethoscope

Question 14

how is heart rate and pulse rate measured?

Answer 14

bpm : beats per minute

Question 15

Why does heart rate increase during exercise?

Answer 15

So that sufficient blood is supplied to working muscles , to provide them with enough OXYGEN and GLUCOSE for increased RESPIRATION

increase in heart rate allows carbon dioxide to be removed at a faster rate

also likely that muscle cells have been respiring anaerobically during exercise so have a built up of LACTIC ACID

heart continues to beat fast after exercise to ensure enough oxygen is still being delivered to muscle cells ( to repay oxygen debt )

extra oxygen used to break down lactic acid that has been built up

Question 16

Describe coronary heart disease

Answer 16

1. Heart is made of muscles cells that need their own supply of blood
   - blood is supplied by coronary artery
   -coronary artery becomes blocked by fatty deposits called plague, artery becomes narrow , reducing blood flow to cardiac muscles
   - reduces oxygen and glucose supply to heart muscle tissue, decreasing rate of respiration and less energy released
   Resulting in death of muscle tissue , muscle cannot contract, heart attack occurs or severe chest pains

Question 17

Describe the difference between partially and completely block coronary artery

Answer 17

partial : restricted blood flow
: resulted in severe chest pains called angina

Completely : area of heart not able to respire
: can no longer contract , leading to heart attack

Question 18

Describe the risk factors for coronary heart disease

Answer 18

• poor DIET has too much saturated fats
• SMOKING as nicotine damages heart and blood vessels
• STRESS increase blood pressure
• OBESITY put extra strain on heart
• LACK OF EXERCISE heart muscle loses its tone and inefficient in pumping blood
• INHERITED heart diseases can pass on rom generations
• GENDER males more likely
• AGE older more vulnerable

Question 19

describe the roles of diet and exercise in reducing risk of coronary heart disease

Answer 19

quit smoking
reduce cholesterol intake, eat more fruits and vegetables
exercise regularly as this will help with reducing cholesterol levels and help strengthen the heart muscles

Question 20

Describe the structure of artery & functions

Answer 20

Functions:
carry oxygenated blood except pulmonary artery away from heart to body tissue

adaptations :
1. thick muscular wall ( withstand high blood pressure )
2. Small lumen ( maintain high blood pressure , more resistance to allow blood push through )
3. Elastic fibre ( Allow artery to stretch and recoil and to maintain high blood pressure
4. Fibrous tissue ( prevent bursting of artery )
made of collagen to maintain structure , gives support

Question 21

Describe the structure of veins & functions

Answer 21

Transport deoxygenated blood into heart except pulmonary vein , transport blood at low pressure

Adaptations :
thin and less muscular wall ( maintain low blood pressure )
wider lumen ( maintain low blood pressure )
has valve ( prevent backflow of blood , to allow blood to flow in one direction )

Question 22

Describe the structure of capillaries & functions

Answer 22

Allows exchange of substance between blood and body cells

One cell thick ( to allow shorter distance for diffusion of substance into body cells )
Large surface area ( rapid diffusion of substance )
Has pore ( allow substances to leak out of the blood into body cells )

Question 23

Name the blood vessels that go in and out of kidney , liver, lungs,

Answer 23

Kidney ( renal artery and vein )
Liver ( Hepatic artery and vein )
Lungs ( pulmonary artery and vein )

Question 24

State the components of blood

Answer 24

plasma ( 55% ) liquid part
RBC
WBC
Platelets

Question 25

describe the adaptations of red blood cells and its functions

Answer 25

1. Biconcave shape - larger surface area to transport oxygen 2. No nucleus- more space for haemoglobin to transport more oxygen 3. contains haemoglobin to transport oxygen

Question 26

describe the adaptations of white blood cells and its functions

Answer 26

1. Made in bone marrow and lymph nodes 2. 2 types : Lymphocyte / phagocyte Lymphocyte : large nucleus ( produces antibodies ) Phagocyte : lobed nucleus ( allows phagocytosis )

Question 27

describe the adaptations of platelets and its functions

Answer 27

- no nucleus - made in bone marrow - involve in clotting

Question 28

What does plasma transport?

Answer 28

- dissolved nutrients ( gluocose, vitamins, minerals, amino acids ) - plasma proteins ( albumin, fibrinogen, antibodies ) - metabolic waste products ( urea, lactic acid ) - carbon dioxide - enzymes and hormones - heat

Question 29

Processes of lymphocytes and phagocytes

Answer 29

Phagocytes : Carry out phagocytosis by engulfing and digesting pathogens have a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells engulf it and released digestive enzymes to digest it Lymphocytes: Produce antibodies to destroy pathogenic cells and antitoxins to neutralise toxins released by pathogens

Question 30

Describe how the 2 types of white blood cells look like under microscope

Answer 30

Phagocytes : multi-lobed nucleus and their granular cytoplasm Lymphocytes : a large round nucleus which takes up nearly the whole cell and their clear, non-granular cytoplasm

Question 31

Describe the process of blood clotting

Answer 31

1. blood vessel are damaged 2. platelet becomes sticky and releases chemical which converts prothrombin to thrombin ( inactive to active enzyme ) 3. thrombin converts soluble fibrinogen to insoluble fibrin 4. fibrin forms a mesh of fibre to trap RBC which eventually dries up and forms scab

Question 32

State the importance of blood clotting

Answer 32

to prevent entry of pathogens into the wound and to prevent blood loss