Role of Baroreceptors in Blood Pressure Control

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BIO WORKSHEET
Weighting: 20% final grade
Answers must be in an easy to read colour that is distinctly different to black.
QUESTION 1
Which type of immunity is expressed in the following scenarios? Choose between:
 Non-specific (first line defence)
 Specific (antibody-mediated)
 Specific (cell-mediated immunity)
(0.5 mark each – total 2 marks)
Scenario Type of immunity
Bacterial septicaemia (bacterial
contamination in systemic circulation)
Specific (antibody mediated)
The pH of hydrochloric acid in the
stomach acts to destroy ingested
bacteria
Non-specific
A liver cell mutates and becomes
cancerous
Specific cell mediated immunity
A virus multiplies inside the epithelial cells in
your throat.
Specific antibody mediated immunity

QUESTION2
Choose TWO of the below scenarios and highlight these rowsbold. State which general property of
adaptive immunity the scenario illustrates in the second column. Select ONE phrase (from the list
below) that BEST describes what is happening at a cellular level to result in this property of adaptive
immunity. Write the letter corresponding to this phrase in the third column. An example is included.
(2 mark)
Scenario General
property of
immunity
Explanation
Even though your body contains a relatively small number of
lymphocytes, your immune system can mount a response
against almost any antigen it encounters.
Versatility
A
Generally, after an initial infection, subsequent immune
responses to that antigen are faster, stronger and more
sustained.
Memory
mediated C
You can suffer from ‘the flu’ multiple times throughout your
lifetime.
Antigen
specificity B
Your immune system can distinguish between antigens on your
own cells, and those of an invading pathogen.
Self
recognition G
Possible phrases are listed below. Not all phrases will need to be used and only ONE phrase is required
per row. If you record more than one, you will not be awarded any marks for your explanation.
A There are millions of different lymphocyte populations, each of which is sensitive to a different antigen.
Lymphocytes proliferate when activated by their specific antigen.
B Each T or B cell has receptors that respond to only one antigen and ignores all others.
C Activated lymphocytes produce two groups of cells: one group that attacks the invader immediately, and
another that remains inactive unless it is exposed to the same antigen at a later date.
D Each T and B cell can recognise many antigens and respond to a wide variety of possible threats.
E T cells are versatile because they produce copious quantities of antibodies that can respond to a wide
variety of threats.
F Phagocytes have a reduced ability to destroy pathogens during subsequent infections.
G The immune response ignores self-antigens and targets non-self antigens.
H B cells differentiate into T cells to create a long-lived immune response.
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QUESTION 3
Describe how bone cells respond to the hormones involved in the homeostasis of blood calcium ion
concentration.
(3 marks)
Two hormones namely parathyroid hormone and calcitonin acts on the bone cells to maintain the
homeostasis of calcium in blood.
In influence to parathyroid hormone, bones in body start giving up calcium which increases the amount
of calcium in blood. When there is access of release of this hormone, bone starts releasing the calcium
on higher rates which leads to disease of weak bones know as osteoporosis.
It inhibits the activity of osteoclasts, which are the cells responsible for breaking down bone. When
bone is broken down, the calcium contained in the bone is released into the bloodstream. Therefore,
the inhibition of the osteoclasts by calcitonin directly reduces the amount of calcium released into the
blood. However, this inhibition has been shown to be short-lived.
QUESTION 4
Why is injury to the medulla oblongata usually fatal?
(2 marks)
Damage to the medulla oblongata can cause several functions of the body to be thrown off and even
death. Because cranial nerves run through this section of the brain injury there can cause several
sensory problems. The medulla helps with coordinating very large body movements liking jogging or
climbing. The medulla houses portions of the brain that control what is considered automatic
homeostatic functions as well as some primitive organs. These functions include the control over lungs
and heart too. When MO fails, lungs fail to function and person has to put on life support system, while
heart cannot able to beat with harmony of the body. Other vital organs also affected during the
damage to MO, which most of the time proves to be fatal.
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QUESTION 5
Complete the following table summarising the effects of autonomic innervation on target tissues. You
must include both the effect upon the target tissue and a consequence of this stimulation in your
answer.
The first row has been completed as an example. (1 mark/box; 4 marks total)
Target tissue Effect of sympathetic stimulation Effect of parasympathetic stimulation
Contractile
force of the
heart
Contractile force increases; more blood
pumped from heart
No parasympathetic innervation of
ventricular myocardium; therefore, no
result
Airways in
the lungs
Relaxation of bronchial muscles of lungs
which dilate the airway in lungs.
Contraction of the bronchial muscles of
lungs which constrict the airway in lungs.
Pupil Due to contraction of the radial muscles of
iris, pupil will dilate.
Due to contraction of the circular muscles
of iris, pupil will constrict.
QUESTION6
Using the diagram provided as a prompt, outline the four steps involved in the transmission of an
electrical impulse from the presynaptic neurone to the post synaptic neurone.
(4 marks)
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