BIOL121 Worksheet: Immunity, Bone Cells, Muscle Contraction, Urine Formation

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BIOL121 WORKSHEET
Due:
Submit: via Turnitin link on BIOL121 LEO page
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 (Cell-mediated immunity)
The pH of hydrochloric acid in
the stomach acts to destroy
ingested bacteria
Non-specific (First line defence)
A liver cell mutates and
becomes cancerous
Specific (antibody-mediated)
A virus multiplies inside the
epithelial cells in your throat.
Specific (antibody-mediated)

QUESTION 2
Choose TWO of the below scenarios and highlight these rows bold. 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
Explana
tion
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.
You can suffer from ‘the flu’ multiple times
throughout your lifetime. Tolerance G
Your immune system can distinguish between
antigens on your own cells, and those of an
invading pathogen.
Specificity D
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
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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.
QUESTION 3
Describe how bone cells respond to the hormones involved in the homeostasis of
blood calcium ion concentration.
(3 marks)
Calcium is released from the bone and is triggered by the parathyroid hormone.
Endocrine system is considered as the central regulator that maintains an effective
blood calcium homeostasis and any further alternation in blood calcium level will
display various effects. Bone is a crucial storage sector of calcium that contains
99% of total calcium present in the body that is essential for development and
growth (Hienz, Paliwal & Ivanovski, 2015). Calcitriol regulates the level of calcium
and phosphorus present in the blood that will retain a proper skeletal system.
Osteoclasts is responsible for bone resorption, which releases calcium ions in the
blood that regulates calcium homeostasis in an individual.
QUESTION 4
Why is injury to the medulla oblongata usually fatal?
(2 marks)
Medulla oblongata is located in the brain stem that regulates various involuntary
activity such as digestion, swallowing, breathing, sneezing, blood and heart vessel
function. Any kind of injury to the medulla oblongata is fatal because if the nerves
of medulla oblongata is injured the person might experience disability in muscle
coordination or suffer from paralysis (Budohoski et al., 2016). The person with
injured medulla oblongata can develop vertigo, have difficulty in swallowing or
insensitivity of touch. Hence, all the necessary involuntary action will be hampered
if medulla oblongata is damaged.
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)
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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
Dilation of airways in the lung,
reduce resistance within the
breathing airways with increased
airflow (Widdicombe & Wine,
2015).
Constriction of airways in the
lung, tightening of muscles that
leads to coughing, wheezing and
shortness of breath.
Pupil Dilation of the pupil, leads to
mydriasis
Constriction of the pupil, leads to
innervation in the iris sphincter
(Liu et al., 2017).
QUESTION 6
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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