cgier 27

Question 1

the exchange of gasses between an organism and its environment is

Answer 1

respiration

Question 2

the functions of respiration

Answer 2

• supply 02 to the body
• removes co2 from the body
• aka gas exchange

Question 3

is highly effective in producing ATP from glucose but requires steady 02 levels

Answer 3

aerobic respiration

Question 4

warm blooded animals aka homeotherms have

Answer 4

high 02 requirements and most animals need continuous supply of 02 for cellular respiration .
Level of respiration = oxygen requirement = index of metabolic activity

Question 5

the functions of respiratory system

Answer 5

• helps u breath in and out
• talk and smell
• warms and moistens air to body temp and humidity level
• protects ur airways
• gas exchange

Question 6

Three distinct stages of gas exchange

Answer 6

1- external respiration: transfers 02 into the blood from atompsthere
2- gas transport : transports 02 and c02 in the blood
3- internal respiration: cellular respiration 02 uptake and c02 production within the cells

Question 7

respiratory pathway of external respiration

Answer 7

nostrils -> nasal cavity -> pharynx -> larynx -> trachea -> bronchi-> bronchioles -> alveoli

Question 8

the upper respiratory tract includes

Answer 8

• Nasal Passages, Eustachian Tubes, Middle ear and mastoid cavities
• pharynx and larnyx
• epiglottis

Question 9

The back of the nasal cavities is continuous with

Answer 9

throat aka pharnyx

Question 10

An opening in the floor of the pharynx leads to

Answer 10

larnyx

Question 11

contains vocal cords

Answer 11

larynx

Question 12

larynx contains cartilage embedded in its wall to

Answer 12

prevents the larynx from collapsing

Question 13

— flap that automatically closes off the larynx during swallowing so that food and liquid enter the oesophagus rather than the lower airway.

Answer 13

epiglottis

Question 14

the most common form of infections in the world

Answer 14

respiratory tract infections
- usually viral but can be bacterial
- mild symptoms but can be severe in children, elderly, immuncompromised patients.
- common cold, sore throat, earache, blocked sinuses, nasal congestion

Question 15

is a single tube which branches into left and right bronchus ( one in each lungs )

Answer 15

trachea , surrounded by rings of hyaline cartilage which reinforces the tube walls

Question 16

the lungs they branch extensively into smaller (secondary)

Answer 16

• bronchi and then many bronchioles
  -Ciliated epithelium in trachea, bronchi, bronchioles.

Question 17

Cilia beat upwards pushing the mucus secreted by the goblet cells assisted by the cough reflex

Answer 17

Mucociliary Escalator

Question 18

Bronchioles lead into

Answer 18

bronchiolar/alveolarducts.
these ends in alveoli which are site of 02 and c02 exchange in the bloodstream

Question 19

Gases diffuse freely through the walls of the —- and into the — that surround

Answer 19

alveolus into the capillaries

Question 20

Alveolar wall contains 2 major cell types

Answer 20

Alveolar epithelial cells – Type I and Type II (also called pneumocytes)
1. type 1: squamous and extremely thin cover 95% alveolar surface involved in gas exchnage
2. type 2: granular and roughly cuboidal cover 5% secretes pulmonary surfactant

Question 21

a phospholipid acts as detergent and reduces surface tension to prevent alveoli from collapsing

Answer 21

surfactant

Question 22

surface tension is produced by the

Answer 22

lining of the lungs , surface area is 480 million in alveoli in 2 lungs 70-80 m in adults

Question 23

Some premature babies born under 32 weeks gestation do not secrete

Answer 23

surfactant bc their lungs have immature or insuffienct type 2 penumocyte. This leads to difficulty in lung expansion and alveoli begins to collapse ( atelectasis ) Requires; immediate treatment, mechanical ventilation, oxygen throat, synthetic or natural surfactant

Question 24

Large, spongy, elastic organs within the

Answer 24

thoracic cavity ( left and right lungs , right lung has 3 lobes and left has 2 lobes bc left lung is smaller to give space for the heart) . These lobes are divided into segments

Question 25

is composed of anterior sternum, posterior spinal column, rib cage (12 pairs of ribs), diaphragm

Answer 25

thoracic cage

Question 26

The lungs are covered by a ---

Answer 26

visceral pleura

Question 27

---in contact with the inner wall of the thorax; ---- in between

Answer 27

parietal pleura , pleaural cavity

Question 28

a film fluid in the ---- provided --- for the lungs and the chest wall

Answer 28

pleaural cavity, lubrication

Question 29

are serous membranes (secrete serous mucous). Can become infected resulting in pleurisy

Answer 29

pleural walls

Question 30

has a negative atmospheric pressure of ---- mm Hg. This acts like a suction to keep the lungs ----

Answer 30

Intrapleural space , -4 , inflated

Question 31

Pulmonary ventilation dependent on 3 pressures:

Answer 31

1. Atmospheric pressure 2. Intra alveolar pressure – will always equalise to atmospheric pressure 3. Intra pleural pressure – always negative ( the difference between 2 and 3 is the difference in pressure that drives the air flow, air flows from high to low pressure) - Atmospheric pressure >intra pulmonary pressure >intra pleural pressure

Question 32

In intrapulmonary pressure during inspiration the pressure inside of the lungs ---- as the volume --- and pressure --- during expiration

Answer 32

decreases, increases, increases

Question 33

In intrapleaural pressure , pleaural cavity pressure becomes more --- when chest well expands during --- and returns to initial value as the chest wall recoils

Answer 33

negative , inspiration

Question 34

during each breath, the pressure gradient move

Answer 34

0.5 litres of air into and out of the lungs

Question 35

Why is intrapleural pressure negative?

Answer 35

necessary to prevent lung collapse due to surface tension of the alveolar fluid and the elastic fibres.

Question 36

Pneumothorax

Answer 36

collapsed lung, results from loss of negative intrapleural pressure.

Question 37

breathing is brought by ----- and --- the volume of --- by means of ---- --- and ----

Answer 37

increasing and decrease volume of the thorax respiratory muscles, intercostals, diaphragm

Question 38

taking air into ur lungs is

Answer 38

inhaling/inspiration - active process - volume increases and air pressure( intrapulmonary pressure) in lungs decreases - stimulating the diaphragm so it contracts becomes less flat and lowered. -Also involves the intercostal muscles - short muscles that lie between the ribs. -External intercostal muscles contract as diaphragm is lowered-raising rib cage and pushing sternum outward

Question 39

letting air out of the lungs is

Answer 39

- exhalation/ expiration - passive no energy needed - diaphragm and intercostal releases chest falls inwards - rose of intrapulmonary pressure and reduction of volume -Can be made active (uses energy) by contracting the muscles of the abdominal wall and the internal intercostal muscles – e.g. in a forced exhalation; and during vigorous exercise * Abdominal muscles pull ribs downward and force abdominal contents upward * Internal intercostal muscles contract pulling ribs down = lung volume reduced

Question 40

breathing is controlled by

Answer 40

-respiratory centre of the brain stem -3 groups of neurons located within the medulla oblongata and pons of the hind- brain

Question 41

Medulla * Dorsal respiratory group- stimulates

Answer 41

inspiratory movements

Question 42

medulla * Ventral respiratory group- stimulates

Answer 42

expiratory movement

Question 43

Pons * Pontine respiratory group – divided into two areas

Answer 43

– Pneumotaxiccenter– continuously sends inhibitory signals to the inspiratory center of the medulla, controls the length of each breath – Apneusticcenter-stimulatesthe inspiratory neurons of the dorsal and ventral groups

Question 44

Respiratory rate and depth of inspiration controlled by

Answer 44

Medulla and Pons in response to specific stimuli . Concentration of the chemicals is controlled by chemoreceptors

Question 44

Central Chemoreceptors (in medulla) near inspiratory area is sensitive to

Answer 44

CO2 and H+ concentration in blood  Increased blood CO2 and H+ levels causes excitation of the inspiratory area. Why? – to increase respiratory rate and expel CO2  Low levels CO2 - decrease respiratory rate

Question 45

Peripheral Chemoreceptors in the Carotid artery and Aortic arch sensitive to

Answer 45

increased CO2 and H+ ions concentration and a drop in oxygen

Question 46

Basic breathing rhythm generated by

Answer 46

neuronal oscillatory (i.e. on/off) circuit in inspiratory area

Question 47

Inspiratory circuit fires 2 seconds

Answer 47

→ nerve impulse → diaphragm and external intercostal muscles contract → inspiration

Question 48

Inspiratory circuit dormant 3 seconds

Answer 48

→ expiratory area dormant → expiration by default, becomes active in forceful breathing - 12 breaths/min quiet breathing,

Question 49

more info

Answer 49

But, during exercise expiratory area activated. Also, Pneumotaxic area continuously transmits impulses to inspiratory area which have a negative effect and turn off inspiratory signal [prevents over-inflation of lungs]: – Strong impulse = 0.5 sec inspiration → secondary effect to increase breathing to 30- 40 breaths/min; – Weak impulse = 5 - 7 sec inspiration. * Hering - Breuer Reflex: stretch receptors in lung tissue (see diagram previous slide), bronchi, bronchioles may on activation transmit inhibitory signal via the vagus nerve (X) to the inspiratory area; prevents over-inflation of the lung