3.2 Transport in animals Flashcards
What are three things which affect the need for a transport system?
size
sa:v
metabolic activity
Features of a good transport system?
medium to carry oxygen/nutrients- blood
pump- heart
exchange surfaces- capillaries
Give an example of a single circulatory system.
fish
heart-gills-body-heart
Advantage of double circulatory systems
After going through lungs, heart can increase pressure so it flows more quickly
What are the three layers of an artery?
tunica intima
tunica media
tunica adventitia
Why does the left ventricle need to be so thick?
needs pressure to overcome resistance of systemic circulation
What is the difference between systole and diastole?
systole= contract diastole= relax
Why is the heart myogenic?
it can initiate its own contraction
What are the two heart nodes?
Sino-atrial
Atrioventricular
Describe how a wave of excitation travels through the heart.
SAN node (pace maker) generates wave of excitation Wave of excitation spreads over both artia walls causing atria to contract (systole) At top of septum, AV node delays the wave allowing time for the atria to stop contracting
How does haemoglobin have a high affinity for oxygen?
4 polypeptide chains each have a haem group
Each binds to one oxygen molecule
So it binds to 4 O2 molecules
why does fetal haemoglobin need a higher affinity for oxygen?
(fetal haemoglobin) must be able to bind to oxygen,
in low(er) partial pressure /
in placenta
How is tissue fluid formed?
by pressure filtration through the capillary walls.
Down pressure gradient from capillaries
How are hydrogencarbonate ions produced in erythrocytes?
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
How do substances that are dissolved in the blood plasma enter the tissue fluid from the capillaries?
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)
Why is lignin essential in xylem?
provides, strength / support ;
to waterproof the vessle
prevent collapse of, vessel / tube ;
2 reasons why multicellular organisms need transport systems
Small SA:V- not sufficient O by simple diffusion
Active- many cells respire quickly- need rapid constant O
1 similarity 1 between difference between fish and mammal circulatory system
Similarity-closed
Difference- fish single, mammal double
What does it mean that cardiac muscle is myogenic?
It can contract and relax without receiving signals from nerves
What do the nodes do in regulating heart beat?-describe 1 beat (7)
- SAN (like pacemaker bc sets rhythm) sends rpwave of electrical activity to atrial walls
- Both atria contract at same time
- Non conducting collagen tissue prevents from going straight to ventricles
- Electrical activity goes to atrioventricular node
- Passes electrical activity to bundle of his, but slight delay to ensure atria empty before ventricles contract
- Bundle of his to purkyne tissue in ventricle walls
- Causing them to contract
What is 1) the P wave 2) the QRS complex 3) the t wave Representing on an ECG
1) P= atria contract
2) QRS= ventricles contract
3) T=ventricles relax
Suggest cause of ECG with smaller QRS complex than normal (2)
Ventricle isn’t contracting properly
Because muscle damage/ AVN not conducting impulses properly
Not all the tissue fluid re-enters the capillaries at the vein end of the capillary bed;where does the excess tissue fluid go?
Briefly describe the lymphatic system
Returns to blood through lymphatic system, through lymph vessles.
Valves in the lymph system stop it going backwards, and lymph moves toward main lymph vessels in thorax, where it’s returned to the blood near the heart
Tissue fluid, blood, and lymph. Which is formed from which?
Tissue fluid is formed from blood, and lymph is formed from tissue fluid.
How are arteries adapted for their function? (2)
Arteries have thick muscle layer to withstand high pressure produced when heart beats
Folded inner lining/endothelium allows arteries to expand to cope with high pressure.
How are capillaries adapted for their function? (1)
Capillary walls are only 1 cell thick, so they have a short diffusion distance for oxygen to quickly diffuse across.
How are veins adapted for their function? (1)
Veins contain valves to stop blood flowing backwards.
What does affinity for oxygen mean?
Tendency to combine with oxygen
When would oxyheamaglobin unload its oxygen?
When there is a low partial pressure of oxygen
Why is an oxygen dissociation curve s shaped (x=partial Pressure of O2, y=saturation of oxyhaemaglobin)
When the 1st O2 binds, haemoglobin shape alters Malkin it easier for other molecules to join, but as it becomes more saturated, it becomes harder for oxygen molecules to bind. So, curve is steep when easy and shallow at each end where it’s harder.
In what way does the partial pressure of carbon dioxide affect oxygen unloading? (1)
Haemoglobin releases oxygen more readily at higher partial pressures of carbon dioxide.
Is bradycardia fast or slow heart rate?
slow
is tachycardia fast or slow heart rate?
fast
which heart problem refers to atria contracting more frequently than ventricles?
atrial fibrillation
