Module 3 Flashcards
1
Q
Alveoli
A
Tiny air sacs that serve as primary gas exchange surface.
Have a thin epithelial cell layer, collagen and elastin fibres
2
Q
Breathing rate
A
Number of breaths per min
3
Q
Bronchi
A
Divisons of trachea that lead into lungs. Small tubes supported by incomplete rings of cartilage
4
Q
Bronchioles
A
Many divisions of the bronchi. Contain smooth muscle to restrict airflow to the lungs but dont have cartilage. Lined with thin layer of epithelial cells
5
Q
Cartilage
A
Strong, flexible connective tissue that supports the walls of the trachea and bronchi, preventing collapse. Incomplete ring shape
6
Q
Ciliated epithelial cells
A
Specialised cells with tiny hair like cilia found in trachea lining that waft mucus up to back of throat- swallow
7
Q
Countercurrent flow
A
Adaption for gas exchange in bony fish.
Blood in gill filaments and water moving up the gills flow in opposite directions, maintaining steep o2 gradient
8
Q
Elastic fibre
A
Fibres of elastin that allow alveoli to stretch as air is drawn in and recoil to normal size- expelling air. Found in trachea, bronchi and bronchioles
9
Q
Exchange surface
A
Surface where materials are exchanged from one region to another. Effective exchange surface has a large SA, thin layers, good blood supply and ventilation to maintain steep diffusion gradient
10
Q
Expiration
A
Diaphragm relaxes and reverts to a dome. External intercostal muscles relax, moving ribs down and in
Volume of thorax decreases and thoracic pressure exceeds air pressure and air moves out
11
Q
Gill filaments
A
Main site of gas exchange in fish, which water flows.
Found in large stacks, known as gill plates and have gill lamellae- large SA for exchange
12
Q
Gill lamellae
A
Fine branches of filaments. Adapted for gas exchange by large SA and good blood supply
13
Q
Gill plates
A
Large stacks of gill filaments
14
Q
Gills
A
Organs of gas exchange in fish. In gill cavity made up of gill lamellae, filaments and plates
15
Q
Goblet cells
A
Specialised cells that secret e mucus onto trachea lining. Mucus traps harmful substances and microorganisms preventing their entry into lungs
16
Q
Inspiration
A
Diaphragm contracts and flattens and external intercostal muscles contract, moving ribs up and out
Volume of thorax increases and thoracic pressure falls below air pressure
Air moves into trachea
17
Q
Internal intercostal muscles
A
Muscles found between the ribs which are responsible for forced exhalation
18
Q
Operculum
A
A flap which covers gills of bony fish. Protects gills and helps maintain a constant stream of water over them
19
Q
Smooth muscle
A
Involuntary muscle found in walls of trachea and bronchi.
Constricts the lumen of bronchi by contracting, reducing air flow to lungs
20
Q
Spiracles
A
Small external openings along the thorax and abdomen of most insects, through which air enters, and air+water leave the gas exchange. Spirical sphincters open and close the spiricals to control gas exchange
21
Q
Spirometer
A
Device to examine patterns of breathing and determine different aspects of lung volume
22
Q
Tidal volume
A
Volume of air that moves in and out of lungs during a normal breath
23
Q
Trachea (mammals)
A
Primary airway which carries air from nasal cavity down to the chest.
24
Q
Trachea (insects)
A
Large tubes from spiracles, into and along an insects body. Supported by spirals of chitin.
25
Tracheal fluid
Fluid found at end of tracheoles. Amount of fluid effects SA available for gas exchange and water loss
26
Tracheoles
Divisions of tracheae that run through tissues of an insect, forming complex network. Main site of gas exchange and completely permeable to gases
27
Ventilation
Movement of fresh air into lungs and stale air out of lungs via inspiration and expiration
28
Vital capacity
Largest volume of air that can be breathed in following strongest possible exhalation
29
Affinity
Tendency of one substance to bind with another
30
Aorta
Artery that takes up oxygenated blood away from heart to body
31
Arteriole
Type of blood vessel which connects arteries and capillaries. Walls of arterioles contain large amount of smooth muscle, some elastic fibres and some collagen
32
Artery
Type of blood vessel that carries blood away from heart to tissues, under high pressure. The walls of arteries contain collagen, smooth muscles and elastic fibres
33
Atrial fibrillation
Arrythmia which involves rapid contraction of atria, preventing complete ventricular filling
34
Atrial systole
Stage of cardiac cycle in which atria contract, pushing blood into ventricles. AV valves pushed open fully and atria emptied of blood
35
AVN
Group cells located between atria that slows down the wave of excitation and pass between ventricle along bundle of his
36
AV valves
Valves found between atria and ventricles. Prevent backflow of blood from venticles into atria. Two typesL Bicuspid and tricuspid
37
Bicuspid valves
AV valves found between left atrium and left ventricle
38
Blood
Transport medium in mammalian circulatory system. Consists of plasma, red blood cells, white blood cells and platelets
39
Bohr effect
Loss of affinity of haemoglobin for oxygen as partial pressure of co2 increases
40
Bradycardia
Slow resting rate below 60bpm
41
Bundle of his
A collection of purkyne fibres which run from AVN down to apex of ventricles
42
Capillaries
Blood vessels that form a large network through tissues of body and connect arterioles to venules. Site of exchange of substances between blood and tissues
43
Carbonic anhydrase
Enzyme which catalyses the reversible reaction between water and co2 to produce carbonic acid
44
Cardiac cycle
Sequence of events in one complete contraction and relaxation of the heart. Arteriole systole, ventricular systole and diastole
45
Cardiac output
Volume of blood pumped by the heart through the circulatory system in one min
Cardiac output = heart rate x stroke volume
46
Chloride shift
Chloride ions move into erythrocytes in exchange for hydrogen carbonate ions which diffuse out erythrocytes. Maintains electrochemical equilibrium of the cell
47
Circulatory system
Transport system in animals
48
Closed circulatory systems
Circulatory system where blood pumped in heart is contained in blood vessels. Blood doesnt come into direct contact with cells
49
Diastole
Stage of cardiac cycle which heart muscle relaxes. Atria and ventricles fill with blood
50
Double circulatory system
Circulatory system which blood flows through the heart twice in two circuits. Blood pumped from heart to lungs before returning to heart.
Then pumped around body where returns to heart
51
Ectopic heartbeat
Additional heartbeats outside normal heart rhythm
52
ECG
Indirectly measures the spread of electrical activity through the heart by measuring tiny changes in the skins electrical conductivity. Produces a trace which is used to detect abnormalities in heart rhythm
53
Haemoglobin
Red pigments in erythrocytes which binds reversibly to four oxygen molecules to form oxyhaemoglobin. Globular protein that consists of 4 polypeptide chains each with a prosthetic haem group
54
Haemoglobinic acid
Product formed when haemoglobin accepts free hydrogen ions.
Enables haemoglobin to act as buffer, reduce changes in blood PH
55
Heart rate
Number of times heart beats in one minute
56
Hydrostatic pressure
Pressure exerted on sides of vessels by a fluid
57
Inferior vena cava
Vein which returns deoxygenated blood to heart from lower body
58
Lymph
Modified tissue fluid which drains into the lymphatic system. Carries less oxygen and fewer nutriens than tissue fluid
59
Myogenic
Cardiac muscle tissues which initiates its own contraction without outside stimulation from nervous impulses
60
Oncotic pressure
Movement of water into blood by osmosis due to tendency of plasma proteins to lower water potential of blood
61
Open circulatory system
Circulatory system in which the transport medium pumped by the heart is not contained within vessels, but moves freely.
Transport fluid comes into direct contact with cells
e.g. Invertibrates
62
Oxygen dissociation curve
Graph which describes relationship between partial pressure of 02 and percentage saturation of Hb in blood
63
Plasma
Main component of blood that carries red blood cells
Yellow liquid that carries proteins, nutrients, mineral ions, hormones
64
Pulmonary arteries
Arteries which carry deoxygenated blood away from heart to lungs
65
Pulmonary veins
Veins which carry oxyenated blood from lungs to heart
66
Purkyne tissue
Specialised cardiac muscle fibres which make up the bundle of His and conduct the wave of excitation through the septum, from AVN down to the apex of ventricles
67
Semi lunar valves
Valves found between ventricles and arteries. Prevent backflow of blood from arteries into ventricles
68
Septum
Wall of muscle seperating left side of heart from right, preventing oxygenated and deoxygenated blood mixing
69
Single circulatory system
Circulatory system which blood travels one circuit. Blood travels through heart and pumped around the body before returning to the heart.
In fish
70
SAN
Group of cells in the wall of right atrium that generate electrical activity causing atria to contract. Hearts pacemaker
71
Stroke volume
Volume of bomb pumped by left ventricle
72
Superior vena cava
Vein which returns deoxygenated blood to heart from head and upper body
73
Tachycardia
Resting heart rate over 100bpm
74
Tissue fluid
Fluid surrounding cells of animals
75
Tricuspid valves
AV valves found between right atrium and right ventricle
76
Vein
A blood vessel which carries blood towards the heart under low pressure. Have a wide lumen, smooth inner lining and valves. The walls of veins contain large amounts of collagen, smooth muscle and elastic fibre
77
Ventricular systole
Stage of cardiac cycle in which the ventricles contract, pushing blood into the arteries. Semi lunar valves are pushed open fully
78
Venule
Blood vessel which connects the capillaries and veins. Walls of the venues contain small amounts of collagen and smooth muscle
79
Active loading
Process which hydrogen ions are actively pumped out of companion cells using ATP, before diffusing down a conc gradient, back into cells via cotransporter proteins whilst carrying sucrose
80
Adhesion
Hydrogen bonds between carbohydrates in xylem vessel walls and water molecules. Capillarity of water and transpiration pull
81
Apoplast route
One of two pathways by which water and minerals move across the root. Water moves through intracellular spaces between cellulose molecules in cell wall
82
Casparian strip
Waterproof strip surrounding the endodermal cells of the root that blocks the apoplast pathway, forcing water through symplast route
83
Cohesion
Formation of hydrogen bonds between water molecules
84
Cohesion-tension theory
Explains movement of water from soil to leaves, in a continuous stream
85
Companion cells
Active cells of phloem located adjacent to the sieve tube elements. They retain their nucleus and organelles, producing ATP for metabolic processes in both themselves and sieve tube elements
86
Dicotyledonous plants
Plants which produce seeds that contain two cotyledons. Two primary leaves
87
Hydrophytes
Plant which is adapted to live and reproduce in very wet habitats
88
Phloem
Living plant transport vessel responsible for transfer of assimilates to all parts of the plant. Contains sieve tube elements and companion cells
89
Plasmodesmata
Small pores between adjacent seive tube elements and companion cells that allow communication and exchange of materials
90
Potometer
Apparatus used to measure water uptake from a cut shoot
91
Root hair cells
Specialised cells responsible for uptake of water and minerals from the soil. Long hair like extensions called root hairs, adapted for exchange surfaces
92
Seive plates
Perforated end walls of seive tube elements that allow plant assimilates to flow between cells unimpeded
93
Seive tube elements
Main cells of the phloem. Elongated cells laid end to end with seive plates between. Contain few organelles
94
Sinks
Regions of a plant which removes assimilates
95
Sources
Regions of plants that produces assimilates
96
Symplast route
One of two pathways which water and minerals move across the route. Water enters the cytoplasm through the plasma membrane and moves between adjacent cells via plasmodesmata. Water diffuses down its water potential gradient by osmosis
97
Translocation
Movement of organic compounds in the phloem from source to sink
98
Transpiration
Water loss from plant leaves and stems via diffusion and evaporation. Rate of transpiration is effected by light, temp, humidity air movement and soil water availablitg
99
Transpiration stream
Flow of water from roots to leaves in plants, where it is lost by evaporation to environment
100
Vascular bundle
Vascular system in herbaceous dicotyledonous plants. Consists of two transport vessels, xylem and phloem
101
Xerophytes
Plants adapted to live and reproduce in dry habitats where water availability is low etc cacti
102
Xylem
Non living plant transport vessel responsible for transfer of water and minerals from roots to shoots and leaves
103
Two types of epithelial cells in lungs airways
Ciliated and squamous
104
How do alveoli create a surface for efficient gas exchange system
Wall is one cell thick for shorter diffusion distance
Large amount of them provide large SA
Cells secrete surfactant to maintain SA
Small size - larger SA:V ratio
105
What is tidal volume
Volume of air inhaled in each breathe
106
What is vital capacity
Maximum volume of air inhaled in one breath
107
Significance of SA:V ratio relationship w rate of diffusion in large plants
Large plants have a low SA:V RATIO , so diffusion is too slow to supply requirements so needs a transport system for water etc
108
How does Squamous epithelium improve efficiency of gas exchange
Shorter diffusion distance,
109
During the electrical stimulation of the heart, there is a short delay between the excitation of the atria and excitation of the ventricles.
Explain why this delay is essential
To allow time for the atria to fully contract
And so ventricles don’t contract too early
110
Purkyne tissue carries the excitation wave down the septum to the apex of the heart. Explain why the excitation wave is carried to the apex.
So that ventricular contractions start at apex to push blood upwards
Complete emptying of ventricles
111
One of the symptoms of smoking is the development of a smoker’s cough.
Explain how smoking causes a smoker’s cough and how the cough itself can lead to further problems in the lungs over a long period of time.
Causes tar
Mucus builds in airways build up
Cigarette smoke stimulates goblet cells to release more mucus
Effects
Formation of scar tissue
Frequent coughing damages airway
Flow of air restriction
112
Lungs contain many air sacs, what’s their name an why there are so many
Alveoli provide larger SA
113
What are the role of elastic fibres in alveoli during ventilation
To prevent bursting
To recoil
114
b) For efficient gaseous exchange to occur, a steep diffusion gradient must be maintained between the air in the air sacs and the blood.
A steep diffusion gradient can be maintained by ventilating the lungs. This refreshes the air in the air sacs.
(i) Explain how refreshing the air in the air sacs helps to maintain a steep diffusion gra
Increases partial pressure of oxygen in air sac
So conc of o2 in the air sac is higher than that in the blood
115
Describe and explain one other way in which a steep diffusion gradient is maintained in the lungs.
Continuous blood flow in the capillaries to bring in more co2
116
Using the mammalian gaseous exchange system as an example, explain how the different cells and tissues enable the effective exchange of gases.
Thin epithelium provides short diffusion distance
Erythrocytes transports gases to and from exchange system
Ciliated epithelium removes dust
Cartilage holds airway open
117
Describe how the spirometer would be used to measure tidal volume.
Not breathing through nose
Measures height of waves from trace
Measure three and find mean
118
Describe how you could use a spirometer trace to measure the rate of oxygen uptake
Measure vol of o2 used
Find difference in height of two peaks- vol changed
Measure time taken to use o2
Volume/time
119
As part of an allergic response, certain cells in the lungs release histamine.
Histamine is a cell signalling molecule that stimulates smooth muscle in the wall of structure A
to contract.
Suggest how histamine stimulates smooth muscle contraction
Histamines bind to receptors on cell surface as has complementary shape
Triggers response in cell
120
Another action of histamine is to make capillary walls more permeable.
Suggest two effects this increased permeability may have on the surrounding tissue
More tissue fluid formed
Increase pressure in tissue
Swelling
More white blood cells pass into tissue
121
What’s the process of cardiac cycle
Atrial walls start to relax and ventricle walls start to contract
SAN generates electrical signals and walls of atria contract
AVN recieves electrical signals from SA node and electrical signals transmitted down septum
Ventricular walls contact and AV valves close
Ventricular valves relax and semilunar valves close
122
What might superventricular tachycardia do to blood flow from heart
Lower output of blood leaves heart for each ventricular contraction
Ventricles don’t have enough time to fill before contraction.
123
Why is the foremen ovals open in foetus before birth
Lungs not functioning
Haemoglobin not oxygenated in the lungs
Pulmonary circuit bypassed
124
State one difference between fetal haemoglobin and adult haemoglobin and give one reason why this difference is essential to the foetus
Fetal Haemoglobin in has a higher affinity for o2
As there is lower partial pressure in placenta
125
What is the role of Haemoglobin in transporting o2
Haemoglobin has a high affinity for o2
Oxygen binds to Hb in lungs
Oxyhaemoglobin
126
How are hydrocarbonate ions produced in erythrocytes
Co2 enters erythrocytes
Co2 combines with water
Forms carbonic acid
127
High concentrations of carbon dioxide in the blood reduce the amount of oxygen transported by haemoglobin.
Name this effect and explain why it occurs
Bohr effect
Reduces affinity of Hb for oxygen
Alters structure of Hb
128
Describe how the components of tobacco smoke can affect the cardiovascular system of smokers.
Nicotine increases stickiness of platelets
Thrombosis causes release of adrenaline
Causes constriction of arterioles
Carbon monoxide
Combines permenantly Hb
Reduces o2 carrying capacity of blood
129
Why is the fetal haemoglobin curve to the left of the adult Haemoglobin curve
Placenta has a low po2
Adult oxyhaemoglobin will release o2
Fetal Haemoglobin has higher affinity for o2
130
Describe and explain how substances that are dissolved in the blood plasma, such as oxygen or glucose, enter the tissue fluid from the capillaries.
Diffusion from high conc to low conc
Hydrostatic pressure in capillary higher than in tissue fluid
Capillary walls are leaky
Fluids forced out capillary
131
Explain why cartilage is essential in the trachea.
Provides strength to keep airway open
During inspiration volume of thorax increases
Lower pressure in lungs
132
What causes the fluctuation of pressure as blood flows along the aorta
Systole increases pressure
Diastole decreases pressure
Contraction of ventricle
133
Describe the pressure changes in blood as if flows through circulatory stem from aorta to veins
Pressure drops as distance from heart increases
Greatest pressure drop whilst blood in arteries
Pressure constant in veins
134
Describe and explain how the wall of the artery is adapted to withstand and maintain high hydrostatic pressure
Withstand
-Wall is thick
-Thick layer of collagen which provides strength
-Endothelium folded so not damaged when stretched
Maintain
-Thick layer of smooth muscle which constricts lumen
-Thick layer of elastin which causes recoil
135
Why is the wall of the left ventricle thicker than wall of left atrium
More muscle to create more force which is needed to create a higher pressure
Push blood against greater resistance
Pushes blood further to all parts of body
136
How do pressure changes in heart bring about closure of AV bicuspid valve
Ventricular systole raises ventricular pressure and higher than atrial pressure
Chordae tendinae prevents inversion
137
What’s the role of SAN and AVN in coordinating cardiac cycle
SAN is pacemaker of the heart and sends impulses over atria walls
AVN delays impulse and sends impulses down septum
138
How is hydrostatic pressure generated in the heart
Contraction of ventricle wall
139
How is action of heart initiated and coordinated
SAN initiates excitation
Wave of excitation spreads across over atrial muscle
Atrial systole
Contraction is synchronised
Delay at AVN
Excitation down septum
140
What are the pores which most water vapour is lost form a leaf
Stomata
141
How are guard cells surrounding the leaf pores adapted to their role
Have an unevenly thickened cell wall which is able to change shape and bend
Prescience of chloroplasts to produce ATP
142
How does the cohesion tension theory explain how water moves from roots to leaves
Evaporation at top of xylem
Creates tension in xylem
Water molecules are cohesive
143
What is a transpiration and a transpiration stream
Transpiration
- loss of water vapour from Ariel parts of stomata
Transpiration stream
-movement of water up xylem vessels from roots to leaves
144
How does active loading take place
Hydrogen ions pumped up companion cells
Increases hydrogen ion conc gradient outside companion cells
H ions flow back into companion cells
Sucrose moves with H ions down conc gradient
145
What are xerophytic features of a leaf and explain how each feature reduces loss of water vapour
Thick cuticle reduces evaporation through leaf surface
Folded r which reduces exposed SA
Has hairs which trap water vapour
146
What sugar molecule is most commonly translocated
Sucrose
147
Two adaptions of seive tubes that enables mass flow
Elongated elements join end to end
No nucleus
148
How are assimilates loaded into phloem
Active transport of H ions creates conc gradient
Facilitated diffusion of h+ into companion cells
Sucrose move in with h ions by cotransport
Sucrose diffuses through plasmodesmata into seive tube
149
How does transpiration contribute to mechanism of water transport up stem
Water loss from leaf is replaced via apoplast/symplast/vacuolar pathway
Down water potent gradient
By water in xylem
In xylem loss of water causes low hydrostatic pressure at top
Water moves down pressure gradient under tension in mass flow
150
Two adaptions of leaves which reduce evaporation
Hairy leaves trap water vapour
Fewer stomata reduces diffusion
151
Significance of relationships between rate of diffusion an SA:V for large plants
Large plants have a small Sa:V
Diffusion too slow to supply requirements
