Module 3 (not including 3.3)

Question 1

Tidal volume

Answer 1

The volume of air in each breath

Question 2

Vital capacity

Answer 2

The maximum volume of air that can be breathed in and out

Question 3

Breathing rate

Answer 3

Breaths taken in a certain time

Usually a minute

Question 4

Oxygen consumption/uptake

Answer 4

The rate at which an organism uses up oxygen

Question 5

What is the need for a specialised exchange surface?

Answer 5

In single called organisms substances can diffuse directly across the cell surface membrane.

However in multicellular organisms some cells are deep within the body so diffusion across the outer membrane is too slow

Plus low surface area to volume ratio

Therefore a specialised exchange surface is needed

Question 6

Name and explain features of an efficient exchange surface?

Answer 6

Large surface area
Root hair cells hair tiny hairs to increase the surface area so that more water can be absorbed

Thin layer
Reduces the diffusion distance to increase the diffusion rate

Good blood supply
Maintains a steep concentration gradient by bringing fresh supplies of molecules to one side so diffusion occurs rapidly

Question 7

Goblet cells

Answer 7

Secrete mucus which traps microorganisms and dust particles in the inhaled air to stop them reaching the alveoli

Question 8

Cilia

Answer 8

Moves mucus upwards away from the alveoli towards the throat where it is swallowed preventing lung infection

Question 9

Elastic fibres

Answer 9

In the walls of the trachea,bronchi, bronchioles and alveoli.

Help with breathing out(expiration)

When we breathe in the fibres are stretched but once we breathe out the fibres recoil to push air out

Question 10

Smooth muscle

Answer 10

In the walls of the trachea, bronchi and bronchioles and allows their diameter to be controlled

During exercise it relaxes making tubes wider so there’s less resistance to air flow allowing air in and out the lungs easier

Question 11

Cartilage

Answer 11

Strong but flexible so provides support by stopping the trachea and bronchi collapsing when we breathe in

Question 12

How does gas exchange take place in fish?

Answer 12

Using the counter current flow system in which water containing oxygen enters through the mouth and passé through the gills

Whilst blood flows through the gill plates in the opposite direction in order to maintain a large concentration gradient so that oxygen can diffuse into the blood

Question 13

How does ventilation take place in fish?

Answer 13

The fish opens its mouth
This lowers the floor of the buccal cavity
The volume of the buccal cavity increases which decrease the pressure inside causing water to be sucked in
When the fish closes its mouth the floor of the buccal cavity is raised
This decreases the volume and increase pressure causing water to be forced out the cavity and across the gill filaments
The increase in pressure forces open the operculum allowing water out the gills

Question 14

How to dissect fish gills?

Answer 14

1- wear lab coat and gloves
2- place fish on dissection tray
3- push back operculum and use scissors to remove gills
Then cut each gill arch through the bone at the top and bottom
4- draw the gill and label it

Question 15

How to dissect an insect?

Answer 15

1- hold the insect in place on thee dissecting board using pins
2- cut and remove a piece of the exoskeleton in order to examine the tracheae
3- use a syringe to fill the abdomen with saline solution
4- examine the tracheae under a light microscope using a wet mount slide

Question 16

Why do multicellular animals need a transport system?

Answer 16

To make sure every cell has a good supply of glucose and oxygen as their cells respire very quickly due to the low surface area to volume ratio and higher metabolic rate

Mammals use the circulatory system

Question 17

Double circulatory system

Answer 17

When the blood flows through the heart twice for each circuit of the body

Question 18

Closed circulatory system

Answer 18

When the blood is held in vessels

Question 19

Open circulatory system

Answer 19

When the blood is not held in vessels

Question 20

Arteries

Answer 20

Vessels that carry blood away from the heart under high pressure

Have thick, muscular walls

Question 21

Veins

Answer 21

Vessels that carry blood back to the heart under low pressure

Question 22

Single circulatory system

Answer 22

When blood flows through the heart once for each circuit of the body

Question 23

Describe fish circulatory system

Answer 23

Single circulatory system in which the heart pumps blood to the GILLS to pick up oxygen and then on through the body to deliver oxygen

Question 24

Describe mammal circulatory system

Answer 24

The right side of the heart pumps deoxygenated blood to the lungs known as the pulmonary system

The left side of the heart pumps oxygenated blood to the rest of the body known as the systemic system

Question 25

Capillaries

Answer 25

They’re adapted for efficient diffusion and are one cell thick

Question 26

Arterioles

Answer 26

Have a layer of smooth muscle but less elastic tissue allowing them to expand and contact in order to control blood flow to the tissues

Question 27

Venules

Answer 27

Have thin walls and join together to make veins

Question 28

Tissue fluid

Answer 28

Surrounds cells and supplies them with oxygen and nutrients

Also helps remove waste substances

Question 29

How is tissue fluid formed?

Answer 29

At the arterial end of a capillary, the blood is at a relatively high hydrostatic pressure.

This pressure pushed the blood fluid out of the capillaries through small gaps in the capillary wall.

This forms tissue fluid which contains dissolved oxygen and nutrients.

The tissue fluid surrounds body cells so gases and nutrients can be exchanged across the plasma membrane via diffusion, facilitated diffusion and active transport.

Question 30

How to dissect a heart?

Answer 30

1- use a pig or cow heart
2- you’ll need a dissecting tray, scalpel, apron and lab gloves
3- examine the outside of the heart and identify four main vessels then draw a labelled sketch of the external anatomy
4- cut the heart open to look inside each ventricle and note the thickness
5- do the same for the atria and compare with ventricle walls
6- sketch the internal anatomy of the heart

Question 31

Cardiac cycle

Answer 31

The sequence of events in one full beat of the heart

Question 32

Name the stages of the cardiac cycle

Answer 32

Atrial systole
Ventricular systole
Diastole

Question 33

What happens during atria systole?

Answer 33

The atria contracts when filled with blood which forces the blood through the atrioventricular valves into the ventricles which fill with blood

Question 34

What happens during ventricular systole?

Answer 34

The ventricles contract forcing blood up through the semilunar valves and into the aorta and pulmonary artery.

The atrioventricular valves prevent blood flowing back to the atria

Question 35

What happens during diastole?

Answer 35

The ventricles and atria are both relaxed.

The semilunar valves close as the blood pressure drops causing the atria to fill with blood. As the pressure increases blood returns to the ventricles

Question 36

What is the SAN?

Answer 36

The SAN controls heartbeats by initiating a wave of EXITATION and DEPOLARISATION in order to set heart rate

(Sinoatrial node - pacemaker)

Question 37

Why do we call the heart myogenic?

Answer 37

It can initiate its own contractions without an external stimulus

Question 38

Describe the oxygen dissociation curve for fetal and adult haemoglobin

Answer 38

A fetus receives oxygen through his mother’s blood across the placenta. By the time the mother’s blood reached the placenta most of its oxygen saturation has decreased so it is more deoxygenated. This means that the Grus must have a higher affinity for oxygen in order to survive

Question 39

What shape is the association between the haemoglobin and oxygen?

Answer 39

S shape

Question 40

Describe the haemoglobin

Answer 40

The haemoglobin has a high affinity for oxygen
Each harm group can carry one oxygen molecule
In the lungs, oxygen joins to the iron in the haemoglobin to form oxyhemoglobin
This reaction can be reversed when oxygen dissociates from oxyhaemoglobin near the body cells to become deoxyhaemoglobin

Question 41

One molecule of haemoglobin carries how much oxygen?

Answer 41

Four oxygen molecules

Question 42

Bradycardia

Answer 42

Slow heart rate

Question 43

Tachycardia

Answer 43

Fast heart rate

Question 44

What is the Bohr effect?

Answer 44

As the concentration of CO2 increases, more oxygen is released from the blood causing the curve to shift right