Module 3: Section 1 - Exchange and Transport

Question 1

alveoli?

Answer 1

tiny air sacs that consist of
epithelial cell layer
elastic fibres
collagen

Question 2

bronchi?

Answer 2

divisions of trachea that consist of small tubes
suppoted by incomplete rings of cartilage

Question 3

cartilage?

Answer 3

rings are incomplete to bend
strong & flexible to stop organs from collapsing
connective tissue
provide support

Question 4

smooth muscle?

Answer 4

involuntary muscle
found in walls of trachea and bronchi
controls organs diameter in tubes so when relaxed they widen

Question 5

cilliated epithelium (cillia)?

Answer 5

beats bacteria containing mucus upwards away frm alveoli towards throat (swallowed) to prevent infection
tiny-hair like cillia

Question 6

goblet cells?

Answer 6

secrete mucus into trachea lining
mucus traps harmful microorganisms and dust particles preventing enter to lungs

Question 7

elastic fibres?

Answer 7

allow alveoli to stretch as air is inhaled + recoil as air is exhaled
found in trachea, bronchi, brochioles

Question 8

bronchioles?

Answer 8

small divisions of bronchi

Question 9

trachea?

Answer 9

primary airway which carries air from nasal cavity to the chest

Question 10

ventilation?

Answer 10

movement of fresh air into lungs and stale out via expiration/inpiration

Question 11

what does trachea contain?

Answer 11

C cartilage
smooth muscle
elastic fibres
goblet cells
cilliated epithelium

Question 12

what does bronchi contain?

Answer 12

Small cartilage
smooth muscle
elastic fibres
goblet cells
cilliated epithelium

Question 13

what does alveoli contain?

Answer 13

elastic fibres
squamous epithelium

Question 14

what does bronchioles contain?

Answer 14

smooth muscle
elastic fibres
goblet cells
cillia

Question 15

why do we need exchange surfaces?

Answer 15

to exchange mats such as urea water and oxygen ACROSS PLASMA MEMBRANES

Question 16

squamous epithelium?

Answer 16

Flat, scale-like epithelial cells
thin walls for quick diffusion pathway

Question 17

diffusion is quick when? why?

Answer 17

the SA:V is greater

Question 18

diffusion is slow when? why?

Answer 18

the SA:V is smaller
as larger organisms cells have no direct contact with external environment so diffusion distance is larger

Question 19

why do larger organisms have specialised exchange surfaces?

Answer 19

as they have higher metabolic rate and smaller SA:V so require more oxygen and glucose

Question 20

adaptations for alveoli?

Answer 20

layer of squamous epithelium cells for quick diffusion pathway
partially permeable to allow certain gases across
ventiliation of air for a steep diffusion gradient
large SA to increase rate of gas exchange
good blood supply so gas exchange can be transported

Question 21

ribcage?

Answer 21

consist of ribs that enclose the thorax (chest)

Question 22

diaphragm?

Answer 22

sheet of muscle that moves the ribcage up and out when it contracts

Question 23

external intercostal muscles?

Answer 23

found between the ribs
pull the ribcage up and out when they contract

Question 24

internal intercostal muscles?

Answer 24

found between the ribs pull the ribcage down and in when they contract

Question 25

pleural cavity?

Answer 25

found in thoracic cavity
double membrane
filled with pleural fluid that lubricates lungs
adheres to thoracic cavity and lungs via water cohesion so lungs expands whilst breathing

Question 26

inspiration?

Answer 26

active process requiring energy for muscle contraction

Question 27

expiration?

Answer 27

a passive process

Question 28

events of inspiration?

Answer 28

1. external intercostal muscles contract while internal intercostal muscles relax, moving the ribcage up and out
2. The volume of the thoracic cavity increases
3. diaphragm contracts and flattens, further increasing the volume of the thoracic cavity
4. lung pressure decreases below atmospheric pressure
5. Air flows into the lungs down the pressure gradient

Question 29

events of expiration?

Answer 29

1. external intercostal muscles relax, moving ribcage down and in
2. The volume of the thoracic cavity decreases
3. diaphragm relaxes and unflattens, further decreasing the volume of the thoracic cavity
4. lung pressure increases above atmospheric pressure.
5. Air is forced out of the lungs down the pressure gradient.