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biology year 1 > transport in animals > Flashcards

transport in animals Flashcards

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1
Q

Nicotine is a toxic chemical. Smokers take in low doses of nicotine that are not toxic in the short term, but these low doses affect cardiovascular health in the longer term.Nicotine increases blood pressure and increases the likelihood of a thrombosis (formation of a blood clot). Either of these effects can lead to a stroke, which is when cells in part of the brain die, leading to loss of function.
(i) Suggest how each of these stated effects of nicotine could contribute to cell death in the brain.

A

increased blood pressure
B1 (small) blood vessels / capillaries, burst / break ;
B2 bleeding causes (localised) build up of
pressure (leading to cell death)
or
blood / oxygen , supply , reduced / stopped ;
B3 cells cannot respire (leading to cell death) ;
thrombosis
T1 thrombus / clot , interrupts / reduces, blood flow ;
T2 (cells) deprived of , oxygen / glucose ;
T3 cells cannot respire (leading to cell death) ;

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2
Q

The blood circulatory system of a mammal undergoes changes at, or soon after, birth.
One of these changes is that the foramen ovale, a hole in the septum between the right and left atria, closes. In the fetus, the foramen ovale allows blood to flow directly from the right atrium to the left atrium.
Suggest why the foramen ovale is open in the fetus before birth.

A

lungs not, functioning / filled with air ;
blood / haemoglobin, is, not oxygenated in the lungs /
oxygenated in placenta ;
(therefore) pulmonary circuit / lungs, bypassed ;

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3
Q

State one difference between fetal haemoglobin and adult haemoglobin and give one reason why this difference is essential to the fetus.

A

Difference: (fetal haemoglobin) higher affinity for oxygen /
described /
ORA ;
Reason: (fetal haemoglobin) must be able to bind to oxygen,
in low(er) partial pressure /
in placenta /
when adult oxyhaemoglobin dissociates /
when adult haemoglobin dissociates from oxygen;
OR
Difference: (fetal haemoglobin) contains gamma sub-units ;
Reason: creates high(er) affinity for oxygen ;

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4
Q

Blood contains erythrocytes and neutrophils. Tissue fluid may contain neutrophils but does not contain erythrocytes.
Tissue fluid is formed from plasma by pressure filtration through the capillary walls. All materials exchanged between the blood and cells pass through the capillary wall.
Explain why tissue fluid does not contain erythrocytes.

A

gap(s) between endothelium cells (too) small ;
(erythrocytes) too large / cannot change shape (much) ;
to, fit / move / pass, between (endothelium) cells OR
through, gaps / pores / fenestrations;

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5
Q

Erythrocytes are full of haemoglobin.

Describe the role of haemoglobin in transporting oxygen around the body.

A

1 (haemoglobin has) high affinity for oxygen ;
2 oxygen binds to haemoglobin in, lungs / alveoli /
high pO2 ;
3 oxyhaemoglobin ;
4 oxygen released, in tissues / where needed / where pO2
is low / where respiration is occurring ;

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6
Q

Most carbon dioxide is transported as hydrogencarbonate ions in the plasma. Hydrogencarbonate ions are produced in the erythrocytes and diffuse into the plasma.
Describe how the hydrogencarbonate ions are produced in the erythrocytes.

A

1 carbon dioxide, enters / diffuses into, erythrocytes ;
2 (carbon dioxide) combines / reacts, with water ;
3 correct ref to carbonic anhydrase;
4 forms carbonic acid ;
5 (carbonic acid) dissociates to form hydrogencarbonate
ions and, hydrogen ions / protons ;
QWC
carbonic acid
carbonic anhydrase,
dissociates (or derivatives of this word)
hydrogen ions / protons

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7
Q

High concentrations of carbon dioxide in the blood reduce the amount of oxygen transported by haemoglobin.
Name this effect and explain why it occurs.

A

Name
1 Bohr (effect / shift) ;
Explanation (any 2 of the following marks)
2 reduces affinity (of Hb) for oxygen ;
3 formation of haemoglobinic acid / hydrogen ions interact
with haemoglobin ;
4 prevents, fall in pH / build-up of H+
, in cells
OR provides buffering effect ;
5 alter, structure / shape, of haemoglobin ;
6 more oxygen released where, needed / more
respiration / carbon dioxide concentration high ;
7 CO2 binds to haemoglobin forming
carbaminohaemoglobin ;

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8
Q

A type of circulatory system that does not keep the blood within blood vessels

A

open (circulatory system) ;

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9
Q

Explain why the fetal haemoglobin curve is to the left of the adult haemoglobin curve.

A

1 placenta has low pO2 ;
2 adult (oxy)haemoglobin will, release O2 / dissociate,
(in, low pO2 / placenta) ;
3 fetal haemoglobin has higher affinity for oxygen /
described ;
4 fetal haemoglobin, is (still) able to take up
(some) oxygen, in placenta / at low(er) pO2 ;

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10
Q

Sickle cell anaemia is an inherited disorder in which haemoglobin crystallises when the partial pressure of oxygen (pO2) is low. The red blood cells change shape and oxygen transport is disrupted.Treatment with drugs, such as hydroxyurea, can stimulate adults to produce fetal haemoglobin rather than adult haemoglobin.
Suggest why this treatment might be of benefit to adults with sickle cell anaemia.

A

fetal) haemoglobin may not crystallise (much)
(at low pO2) ;
red blood cells do not change shape ;
(fetal) haemoglobin can pick up more oxygen at low pO2
(than sickle haemoglobin);
idea that more oxygen, transported / delivered
(around body) ;

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11
Q

Describe and explain how substances that are dissolved in the blood plasma, such as oxygen or glucose, enter the tissue fluid from the capillaries.

A

diffusion ;
from high concentration to low concentration / down
concentration gradient;
(hydrostatic) pressure in capillary high(er than in tissue
fluid) ;
capillary (walls) leaky / described ;
fluid / plasma, forced out (of capillary)
OR
fluid / plasma, moves, from higher pressure to lower
pressure / down pressure gradient ;
(as the fluid / plasma moves out) glucose / oxygen / small
molecules, leave with, fluid / plasma ;
QWC
diffusion / diffuse, pressure, hydrostatic,
concentration gradient

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12
Q

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.

A

(to allow time) for the atria to (fully) contract ;
to allow (time for), atria to empty / blood to move /
ventricles to fill ;
so that ventricle(s) do not contract, too early ;

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13
Q

The 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.

A

so that (ventricular) contraction starts at, apex / base /
bottom ;
to push blood upwards
OR
into/ towards, (named) arteries ;
complete / efficient, emptying of ventricles ;

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14
Q

The pressure fluctuates as the blood flows along the aorta.

Explain what causes this fluctuation.

A

systole / contraction, increases pressure ;
diastole / relaxation/ blood flowing onwards, decreases
pressure ;
(contraction of) ventricle, muscle / wall ;
left (ventricle) ;

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15
Q

State the term used to describe the number of fluctuations per minute.

A

pulse / heart, rate ;

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16
Q

Explain why it is important that the pressure changes as blood flows from the aorta to the capillaries.

A

capillary (wall) is, thin / only one cell thick ;
(high pressure would) burst / damage, capillary (wall) ;
reduce chance of, tissue fluid build up / oedema ;

17
Q

Suggest two advantages of keeping the blood inside vessels.

A

maintain / high(er), (blood) pressure ;
increase rate of, flow / delivery ;
flow can be, diverted / directed / AW ;

18
Q

Describe and explain how the wall of an artery is adapted both to withstand and maintain high hydrostatic pressure.

A 
to withstand pressure
wall is thick ;
(thick layer of) collagen ;
(wall / collagen) provides strength ;
endothelium, corrugated / folded ;
idea of: no damage to, endothelium / artery (wall) (as it
stretches) ;
max 3
to maintain pressure
(thick layer of) elastic tissue / elastic fibres / elastin ;
to cause recoil / return to original size ;
(thick layer of) smooth muscle ;
narrows / constricts, lumen / artery ; 
QWC
withstanding pressure:
collagen endothelium / endothelial
maintaining pressure:
elastic / elastin recoil smooth muscle
lumen constrict(ion)
19
Q

Explain why the wall of the left ventricle is thicker than the wall of the left atrium.

A 
left ventricle
1 (more muscle to create) more force ;
2 (needs to create) higher pressure ;
3 push blood against greater , resistance / friction ;
4 (left ventricle) pumps blood further /
 pumps blood to all parts of body /
 supplies systemic circulation ;
20
Q

Explain how pressure changes in the heart bring about the closure of the atrioventricular (bicuspid) valve.

A 
1 ventricular systole
 or
 ventricle , wall / muscle , contracts ;
2 (ventricular contraction) raises ventricular pressure ;
3 (ventricular pressure) higher than atrial pressure ;
4 idea of (pressure / movement of blood,
 generated by ventricular contraction)
 pushes valve shut ;
5 chordae tendinae prevent inversion ;
21
Q

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 Ato contract.Suggest how histamine stimulates smooth muscle contraction.

A

1 (histamine), binds / attaches, to, receptor
/ glycoprotein ;
idea of :
2 in / on, plasma / cell surface, membrane
(of muscle cell) ;
3 complementary (shape) ;
4 triggers response / causes effect, inside
cells ;

22
Q

Another action of histamine is to make capillary walls more permeable.Suggest two effects this increased permeability may have on the surrounding tissues.

A 
1 (histamine), binds / attaches, to, receptor
 / glycoprotein ;
idea of :
2 in / on, plasma / cell surface, membrane
 (of muscle cell) ;
3 complementary (shape) ;
4 triggers response / causes effect, inside
 cells ;
idea of :
1 more tissue fluid formed / increase in
 volume of tissue fluid ;
2 increase pressure in tissue ;
3 swelling / inflammation / oedema;
4 (more) white blood cells pass into tissues ;
5 larger molecules / (named) proteins ,
 pass into tissue fluid ;
23
Q

Explain why the curve for fetal oxyhaemoglobin is to the left of the curve for adult oxyhaemoglobin.

A

1 fetal haemoglobin has a higher affinity (for
oxygen) ( than adult haemoglobin) ;
2 (fetal Hb) takes up oxygen in low(er) partial
pressure of oxygen ;
3 placenta has low partial pressure of oxygen ;
4 at low partial pressure of oxygen / in placenta,
adult (oxy)haemoglobin will dissociate / AW ;
QWC
affinity, dissociate / dissociation, placenta,
partial pressure / oxygen tension, saturation / saturated

24
Q

Outline the benefits of the Bohr shift to actively respiring tissue.

A

1 (actively respiring tissue) needs / requires,
more oxygen
;
2 for aerobic respiration / to release more
energy ;
3 (actively respiring tissue produces) more CO2
;
4 haemoglobin involved in transport of CO2 ;
5 less haemoglobin available
to combine with O2
;
6 (Bohr shift) causes more oxygen to be
released ;

25
Q

Describe the roles of the sinoatrial node (SAN) and the atrioventricular node (AVN) in coordinating the cardiac cycle.

A

SAN, is pacemaker / initiates heart beat ;
(SAN sends) impulse / wave of excitation,
over atria (walls) ;
AVN delays impulse ;
(AVN) sends impulse down, septum /
bundle of His / Purkyne fibres ;

26
Q

State two other ways in which the wall of an artery is different from the wall of a vein.

A

Arteries have:
no valves ;
endothelium / tunica intima, folded / AW ;
more / thicker, muscle / elastic tissue / tunica media ;
more / thicker, collagen / tunica externa ;

27
Q

Blood in the arteries has a high hydrostatic pressure.State how this hydrostatic pressure is generated in the heart.

A

contraction of ventricle, wall / muscle ;

28
Q

Explain why the hydrostatic pressure of the blood drops as blood moves away from the heart.

A

more, (smaller) vessels / named vessels ;
(vessels) have larger, total lumen / cross sectional
area ;
reduced resistance to blood flow ;
arteries, stretch / expand ;
loss of, fluid / plasma, from capillaries ;

29
Q

State the meaning of the terms single circulatory system and closed circulatory system.

A 
single circulatory system:
blood passes through the heart once for each, circulation /
circuit / cycle, of the body ;
closed circulatory system:
the blood is maintained inside vessels
30
Q

describe how the action of the heart is initiated and coordinated.

A

T / SAN, creates / initiates / starts / originates, excitation ;
wave (of excitation) spreads over atrial, wall / muscle ;
ref to, AVN / U ;
atria contract / atrial systole ;
contraction is synchronised / AW ;
delay at AVN ;
(excitation spreads) down septum ;
ref to, bundle of His / Purkyne fibres ;
ventricles contract / ventricular systole, from, apex / bottom ;
QWC
atrioventricular node, excitation, atrial / atrium /
atria, septum, Purkyne, bundle of His, ventricle(s) /
ventricular, apex, systole.

biology year 1 (15 decks)

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