animal responses

Question 1

Explain why glycogen granules are present in striated muscle.

Answer 1

energy storage ;
hydrolyses / breaks down , to glucose ;
(glucose / glycogen, for) respiration / to make ATP ;
glycogen insoluble / glucose would exert osmotic effect ;

Question 2

State what happens to the lengths of the following when muscle contracts:
A band
H zone
I band

Answer 2

A band stays the same / no change ;
H zone decreases / shorter / smaller ;
I band decreases / shorter / smaller ;

Question 3

During strenuous exercise, the concentration of hydrogen ions in muscle tissue increases.A high concentration of hydrogen ions reduces the ability of calcium ions to bind to proteins in the myofibrils.
This reduces the force with which a muscle can contract.
Use this information and your own knowledge of the proteins in muscle cells to explain how an increased concentration of hydrogen ions leads to a reduction in the force of contraction of a muscle.
In your answer you should make clear the link between the increased concentration of hydrogen ions and the reduction in the force of contraction of a muscle.

Answer 3

(fewer) Ca2+ / calcium ions, bind to troponin ;
(fewer) troponin (proteins) change shape ;
(fewer) tropomyosin (proteins) move aside ;
(fewer) binding sites on actin available ;
(fewer actin-myosin) cross bridges / links, form / AW ;
power stroke reduced / AW ;
actin filaments pulled past myosin with less force ;
ref. pH and denaturing of proteins ;

Question 4

Outline the organisation and roles of the autonomic nervous system in mammals.

Answer 4

(two parts are) sympathetic and parasympathetic ;
S has, short preganglionic neurone / long
postganglionic neurone / ganglia near(er) spinal cord,
but P has, long preganglionic neurone / short
postganglionic neurone / ganglia near(er) organ ;
S uses noradrenaline but P uses acetylcholine (at
organ) ;
S, fight / flight / stress, but P, rest / relaxation / calm ;
S increases, heart rate / cardiac output / blood
pressure, but P reduces this ;
S increases , speed / rate / depth, of breathing, but P
reduces this ;
S increases airway diameter but P reduces it ;
S increases blood flow to skeletal muscle but P
increases blood flow to gut (smooth muscle) ;
S for orgasm but P for sexual arousal ;
S dilates pupils but P constricts pupils ;
S makes liver release glucose, but P makes liver,
store / take up, glucose ;
P allows, peristalsis / digestion, but S reduces it ;

Question 5

The ‘fight or flight’ response is brought about by the hormone adrenaline and the autonomic nervous system working together. As well as causing external differences in appearance, the ‘fight or flight’ response causes numerous changes in the functioning of the internal organs.
Describe how two internal organs would function differently in a calm mammal compared to a frightened mammal

Answer 5

organ calm mammal frightened mammal
heart ; rate slow / small force ; rate fast / great force ; 
lungs ; breathing, slow / shallow ; breathing, fast / deep ; 
(skeletal) 
muscle / 
arteries 
to 
muscle ; 
less, active / blood flow ; more, active / blood flow ; 
liver ; 
glucose  glycogen / 
glucose taken up ; 
glycogen  glucose / 
glucose released ; 
gut / 
named 
part of 
gut ; 
peristalsis / secretions / 
digestion / blood flow to 
gut, occurring ; 
no / less, peristalsis / 
secretions / digestion /
blood flow to gut ;

Question 6

In the table below, state which division of the autonomic nervous system will be active in each case, and name the neurotransmitter that will be secreted by neurones into the organs.
calm mammal frightened mammal

division of the autonomic nervous system activated

name of neurotransmitter secreted by neurones

Answer 6

calm mammal frightened mammal

division parasympathetic ; sympathetic ;
neurotransmitter
acetylcholine / ACh ; noradrenaline / NA norepinephrine /

Question 7

differences between:

the central nervous system and the peripheral nervous system

Answer 7

central
CI brain and spinal cord ;
C2 intermediate neurones ;
C3 has , coordinating role / many synapses ;
peripheral max 3
P1 nerves , from sense organs / to muscles / to glands ;
P2 sensory and motor , neurones / nerve cells ;
P3 role in , sensing stimuli / controlling effectors
or conducting impulses, to / from ,
CNS / brain / spinal cord ;
P4 includes , somatic / autonomic /
sympathetic / parasympathetic ;

Question 8

For each type of muscle, identify where in the thorax this type of muscle may be found.

Answer 8

voluntary
intercostal / diaphragm ; 
involuntary 
bronchi / bronchioles / arteries / arterioles / aorta / 
oesophagus ; 
cardiac 
heart ;

Question 9

) The ‘fight or flight’ response to threatening environmental stimuli is coordinated by the nervous and endocrine systems.Describe and explain how the activation of the ‘fight or flight’ response affects voluntary, involuntary and cardiac muscle.
In your answer, for each type of muscle, you should give a named structure in which it is found and explain how the nervous and endocrine systems affect its response.

Answer 9

appropriate parts of nervous / endocrine systems
sympathetic (motor neurones) stimulated ;
noradrenaline / norepinephrine ;
neurotransmitter released at ,
neuromuscular junction / organs ;
adrenaline (secreted / released into blood) ;
from adrenal , glands / medulla ;
idea of adrenaline / noradrenaline ,
binding to receptors (on target tissue) ;
AVP ;
effect on structures containing 3 types of muscle
idea of heart beats faster ;
idea of heart beats more forcefully ;
alter blood flow / increase blood pressure ;
less blood flow to , gut / skin ;
reducing gut secretions / making skin pale ;
smooth muscle in gut relaxes / peristalsis slows down ;
smooth muscle in airways relaxes / airways wider ;
iris radial muscle contracts / pupil dilates ;
idea of breathing / intercostals contracting /
diaphragm contracting , faster ;
more blood flow to (skeletal) muscles ;
idea of (named skeletal) muscles being primed for action ;