cardiac and respiration

Question 1

what is meant by ‘breathing’

Answer 1

Physical process of inhalation

Question 2

describe the process of inspiration/inhalation

Answer 2

External intercostals contract –> ribcage moves up and out

Diaphragm contracts and flattens

Volume of thoracic cavity increases

• Lungs inflate, increasing volume in the lungs
• Therefore decreasing pressure
• Air travels from H-L pressure into the lungs

Question 3

describe the process of expiration/exhalation

Answer 3

Internal intercostals contract –> ribcage moves down and in

Diaphragm relaxes and forms a dome shape

Volume of thoracic cavity decreases

• Lungs deflate, decreasing volume in the lungs
• Therefore increasing pressure
• Air travels from HL pressure out of the lungs

Question 4

explain the structure of the lungs

Answer 4

Covered by the pleural membrane

The inner layer is attached to the lungs and the outer layer attached to the thoracic cavity

Between the 2 layers is the pleural fluid

It’s attached to the thoracic cavity and reduces friction, protects them as we breathe

Question 5

explain the structure and function of the nasal cavity

Answer 5

Divides into 2 sides, each side has 3 shelves

Contains chemo receptors

Cilia hairs filter. Blood capillaries warms. Mucous moistens.

Question 6

what is the function of the larynx

Answer 6

Allows for speech, vocal cords vibrate to make sound.

Question 7

explain the structure and function of the trachea

Answer 7

Made of c-shaped bands of cartilage that give flexibility and support

Lined with mucous membrane and cells with cilia to trap any solid particles

Cilia beat to move mucous and trapped particles upwards

Question 8

explain the structure and function of the bronchi

Answer 8

Pass air from the trachea into each lung.

Contains cartilage rings and a ciliated mucus membrane

Two bronchi branch from the trachea, one left and one right

Question 9

explain the structure and function of the bronchioles

Answer 9

Very fine tubes that pass air from bronchi to alveoli.

End in tiny air sacs, the alveoli.

Question 10

explain the structure and function of the alveoli

Answer 10

Tiny air sacs at the end of bronchioles

Site of gas exchange

On the outside of an alveolus is a dense network of blood capillaries

One cell layer thick

Cells are moist to increase the rate of diffusion

The huge surface area allows efficient exchange of gasses

Question 11

define gas exchange

Answer 11

Process of oxygen diffusing from the alveoli into the blood and carbon dioxide diffusing from the blood into the alveoli in the lungs.

Question 12

explain the process of gas exchange

Answer 12

Deoxygenated blood comes from the heart via pulmonary artery. There is a high concentration of C02 in the blood capillaries and a low concentration in the alveolus.

Inspired air in the alveolus contains a high concentration of oxygen, and low in the blood capillaries.

Via the process of diffusion carbon dioxide moves from the capillaries (high concentration) to the alveolus (low concentration).

O2 moves from the Alveolus (high concentration) to the blood capillaries (low concentration).

Oxygenated blood in the capillaries returns to the heart via pulmonary veins.

C02 in the alveolus is expired.

Question 13

why are the lungs well suited to the process of gas exchange

Answer 13

1. Alveoli give the lungs a huge internal surface area, so large amounts of gas can be exchanged more efficiently and quickly
2. Each alveolus is well supplied kwith blood vessels, so that as much blood as possible is close to air
3. Alveoli and capillary cell walls are 1 cell thick, so molecules don’t have to travel far when moving in or out of the blood
4. Lung volume can be changed by movements of respiratory muscles, so air is made to flow in and out of the lungs

Question 14

list 2 disorders of the respiratory system

Answer 14

emphysema

asthma

Question 15

explain what emphysema is

Answer 15

Caused by long term exposure to irritating particles in the air taken into the lungs

Irritating particles cause damage to alveoli

They lose elasticity and are replaced with fibrous tissue and may break down, reducing surface area for gas exchange

Lungs become constantly inflated and breathing out is a voluntary effort

Symptoms: frequent coughing/wheezing, cough produces mucous, tightness in chest, shortness in breath especially in physical activity

Treatment: cannot be cured, once lung damage begins progression of disease cannot be stopped

Question 16

explain what asthma is

Answer 16

Difficulty breathing caused by narrowing of airways

Occurs due to: smooth muscles contracting: blocking airways, mucous filling airway, narrowing the tube

Triggers include: respiratory infections, cigarette smoke, allergens e.g. dust, pollen and animals

During asthma attack muscles surrounding the bronchi spasm and cause narrowing of air passages, therefore difficult breathing

Irritation of membrane lining passage secretes excess mucous, restricting movement of air

Gas exchange is reduced and blood doesn’t carry normal amount of oxygen

Symptoms: difficulty breathing, severe chest pain, coughing and wheezing

Treatment: bronchodilator, inhaler, anti-inflammatory medication

Question 17

explain the carrying of oxygen gas

Answer 17

3% is dissolved in blood (plasma)
97& dissolved in oxyhaemoglobin

• At the alveoli oxygen enters into RBCs and attatches to
  the ‘haem’ part of the haemoglobin molecule
• At the cells oxygen breaks off the haemoglobin
  molecule and enters fluid outside of the cell, the moves
  into the cell

Question 18

explain the carrying of carbon dioxide gas

Answer 18

8% dissolved in blood (plasma)
22% dissolved in the ‘globin’ part of haemoglobin in RBCs

• At the cells 22% of CO2 attached to the globin part of
  the haemoglobin molecule
• At the alveoli CO2 breaks away and moves into the
  alveoli to be exhaled

70% converted into bicarbonate ions
- CO2 diffuses out of cell and react with water around
the cell to form carbonic acid
- Carbonic acid ionises to produce H+ ions and HCO3-
ions
- At the alveoli this reaction reverses

Question 19

what is the chemical equation for the conversion of carbon dioxide gas into bicarbonate ions

Answer 19

CO2 + H2O (double arrow) H2CO3 (double arrow) H+ + HCO-3

Question 20

what are the functions of the circulatory system

Answer 20

Body’s main transport system

Link between cellular requirement inside the body and outside environment that supplies these requirements

Blood is the transport link between cells and all the body systems

Some important functions of blood are:
- Transporting oxygen, nutrients and hormones to cells
- Transporting carbon dioxide and waste away from cells
- Maintaining pH and water & ion concentration of body
fluids
- Distribution of heat and maintaining body temperature

Question 21

explain the structure of the heart

Answer 21

Pump that pushes blood around the body

Located between the lungs in the mediastinum & behind and slightly to the left of the sternum

Conical shape approximately 12 cm long, 9 cm at its widest and 6 cm wide

It is enclosed in the pericardium (its membrane)

Wall of heart is made of cardiac muscle

Right side: collects deoxygenated blood from the body and pumps it to the lungs

Left side: collects oxygenate blood from the lungs and pumps it around the body

Each side is separated into 2 chambers: atria & ventricles

Question 22

what is the purpose of the pericardium

Answer 22

• Holds heart in place
• Allows for movement
• Prevents overstretching

Question 23

explain the structure, function and percentage composition of red blood cells in blood

Answer 23

composition in blood: 45%

Biconcave disc shape

No nuclei: more room to carry haemoglobin that binds with oxygen

Flexible: fit through capillaries

Carry oxygen, bound to the protein haemoglobin

Live for approximately 120 days

Produced in red bone marrow

destroyed in liver and spleen

Question 24

explain the structure, function and percentage composition of white blood cells in blood

Answer 24

composition: <1%

Larger than RBC but fewer

2 types:
- Granulocytes: granular cytoplasm and spherical
nucleus
- Monocytes and lymphocytes: agranular cytoplasm and
spherical nucleus

Able to change shape

Removes dead/injured cells and invading organisms/pathogens

Question 25

explain the structure, function and percentage composition of plasma in blood

Answer 25

composition: 55%

91% water

The rest is dissolved substance e.g. ions, gases, hormones

Pale yellow colour

Liquid part of the blood

Question 26

explain the structure, function and percentage composition of platelets in blood

Answer 26

composition: <1%

small cell fragments

no nucleus

formed in red bone marrow

last for 7 days

jagged edges

Question 27

what are the functions of blood clotting

Answer 27

Minimise blood loss

prevent entry of microorganisms

Question 28

what are the 3 stages of blood clotting

Answer 28

vasoconstriction

platelet plug formation

coagulation

Question 29

explain the stage of vasoconstriction in the process of blood clotting

Answer 29

Blood Vessel constricts reducing blood flow to that area.

Question 30

explain the stage of platelet plug formation in the process of blood clotting

Answer 30

Walls of blood vessel becomes rough

Platelets in plasma become stuck to the rough walls

More platelets come to the site and stick to each other

Platelets release chemicals which prolong vasoconstriction

Question 31

explain the stage of coagulation in the process of blood clotting

Answer 31

Chemicals form thread-like proteins called Fibrin

Fibrin threads form a mesh network around the plug

Fibrin seals wound from outside the blood vessel wall and traps RBCs

This build up causes a clot

Network of threads contracts and pulls the edges of the damaged vessels together

Fluid gets squeezed out of the cut and dries, causing a scab