Respiratory System Flashcards
(40 cards)
1
Q
internal respiration meaning
A
use of O2 and production of CO2 by cells
2
Q
external respiration definition
A
movement of gases between environment and cells
3
Q
what gradient determines air flow?
A
a pressure gradient (from high to low)
4
Q
what conditions are needed for air to flow into the lungs?
A
- low pressure inside the lungs = higher volume
5
Q
what is bulk flow?
A
movement of fluid as a result of pressure gradient
6
Q
what factors led to an increase in O2 needs
A
- larger size
- endothermy
- habituation of new environments
- large nervous system
7
Q
what are unique features of gills?
A
- highly vascularised
- large SA
- thin membranes
- operculum
- countercurrent exchange -> swimming moves water through gills
8
Q
amphibian respiratory features
A
- combination of skin, gills and lungs
- use buccal cavity to draw in air and squeeze it down mouth
- intermttent breathers
9
Q
reptile breathing
A
- emergence of inspiratory/expiratory
- reduce internal air pressure and suck air into lungs using muscular pumps
10
Q
bird respiratory
A
- need a higher metabolic rate due to more O2 required for flying
- change air pressure in air sacs
- air sacs flow onto lungs
- counter current flow in lungs
- high haemoglobin affinity
11
Q
mammal features
A
- high SA
- upper and lower resp tract
- diaphragm + inter-coastal muscle for pressure gradient
- pleural sac around lungs for inflation
12
Q
what’s included in upper resp tract
A
- oral and nasal cavity, pharynx and larynx
13
Q
what’s included in lower resp tract
A
- trachea, bronchi, bronchioles, alveoli
14
Q
features of upper resp tract
A
- goblet cells and cilia
- cartilage rings in trachea and bronchi
- smooth muscle and no cartilage n bronchioles
15
Q
features of lower tract
A
- large SA
- thin walls
- no goblet cells
- absent cilia (may be sparse)
- no cartilage
- alveolar sac -> clusters of alveoli
16
Q
features of alveoli
A
- single thin epithelial layer
- surfactant secreting type II alveolar cells
- macrophages
17
Q
features of bronchioles
A
- smooth muscle walls
18
Q
features of bronchi
A
- cartilage rings
- ciliated
- epithelium
- goblet cells
19
Q
features of trachea
A
- cartilage rings
- ciliated epithelium
- goblet cells
20
Q
nasal cavity
A
- ciliated epithelium
- goblet cells (mucus)
- hair
21
Q
how is O2 transported in blood
A
- gas transport proteins
- matalloproteins -> carry metal ions which reversibly bind to O2 and increase O2 carrying capacity by 50X
- HEMOGLOBIN in vertebrates is the protein
- contained within red blood cells
22
Q
How is homeostasis related?
A
- blood gas levels are regulated variable
- chemoreceptors are sensors
- medulla = control centre
- effectors = heart, lungs/resp muscles
23
Q
what is partial pressure
A
- fraction of air made up by a particular gas
- pp of individual gas = total pressure of gas x % of individual gas (only at sea level where water = 0%)
24
Q
definition of diffusion of gases
A
movement of gas mols from region of high pp to low pp
25
what is the diffusion coefficient
- measure of permeability of a particular membrane to a particular gas
- constant for each gas
- dependent on solubility and molecular weight
- more soluble = large coefficient
- smaller molecule = diffuse faster = larger co.
- e.g. CO2 more soluble than O2, so at any pressure CO2 dissolves faster in water and crosses membrane faster
26
what is diffusion rate proportional to?
1. surface area
2. diffusion coefficient
3. magnitude of the pp gradient
27
what is diffusion rate inversely proportional to?
membrane thickness
28
What is Fick's law?
V = A x D x ChangeP/T
- diffusion rate = V
- Membrane SA = A
- diffusion coefficient = D
- PP gradient = P = P1 – P2
- membrane thickness = T
29
What is the pressure gradient
- difference in pressure between two areas
- the only factor that can change in the short term
-
30
what is bulk flow
- all air movement due to pressure gradient
- flow (Q) is proprotional to pressure gradient
- flow inversely proportional to resistance (r)
- Q = changeP/R
31
how is a pressure gradient generated?
- change in lung volume due to muscles
- small volume = high pressure due to molecules bouncng off each other and walls
- large volume = more space = less contact
32
what determines resistance
- radius
- flow pattern
- fluid viscosity
- length
33
why does radius have such a large impact on flow
- resistance to the fourth power of r
34
why is resistance lower in bronchioles than trachea
- so many that their total cross sectional area reduces resistance
35
Flow patterns and impact
1. turbulent = slower flow
2. transitional = in between, still bouncing
3. laminar = straight through flow, no bouncing
*highest turbulence in trachea
36
Special properties of flow
1. pressure gradient is variable (resp muscles)
2. bronchioles are collapsible
3. bronchiolar radius can be actively regulated (smooth muscle rings)
37
how s bronchiolar resstance altered passively
- each breath causes changes in thoracic pressure
- this lead to changes in pressure of bronchioles leading to changing radius passively
38
how is bronchiolar resistance altered actively
- smooth muscle contracts or relaxes
- causes longer term variation to resistance
- under intrinsic and extrinsic control
39
local control of smooth muscle
- chemical mediators (CO2) cause dilation
- histamine produces strong bronchoconstruction and mucus -> paracrine hormone = rapid constriction
40
extrinsic control of smooth muscle
- autonomic nervous system and hormones
- parasympathetic nerve system causes contraction input
- sympathetic reacts to adrenaline to cause relaxation
