the answers should be in red.
BIOL121 WORKSHEET
Due: 3 am Tuesday 12th May (Week 11)
Submit: via Turnitin link on BIOL121 LEO page
Weighting: 20% final grade (marked /60)
Please ensure your typed responses are in red.
QUESTION 1: IMMUNE SYSTEM (1.5 MARKS)
Which type of immunity is expressed in the following scenarios? Choose between:
• Non-specific (first line defence)
• Non-specific (second line defence)
• Specific (antibody-mediated)
• Specific (cell-mediated immunity)
(0.5 mark each – total 1.5 marks)
Scenario Type of immunity
Coughing or sneezing.
The hypothalamus raises the body temperature above the normal range, producing fever.
Plasma cells respond to chicken pox virus
QUESTION 2: IMMUNE SYSTEM (2 MARKS)
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. (0.5 mark each – total 2 marks)
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.
You can suffer from ‘the flu’ multiple times throughout your lifetime.
Your immune system can distinguish between antigens on your own cells, and those of an invading pathogen.
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.
QUESTION 3: BONES (3 MARKS)
Describe the role of osteoblasts and osteoclasts in the regulation of blood calcium ion concentration. You must include the role of the relevant hormones for full marks. (3 marks)
QUESTION 4: MUSCLES (3 MARKS)
Define atrophy and use an example to explain how this term relates to skeletal muscle tissue. (3 marks)
QUESTION 5: ENDOCRINE SYSTEM (3 MARKS)
Think about how the renin-angiotensin-aldosterone system acts to maintain normal blood pressure. Susan has sustained damage to her adrenal glands. Consequently, her circulating levels of aldosterone are abnormally low. What do you expect the lack of aldosterone to do to Susan’s blood pressure? Explain your answer. (3 marks)
QUESTION 6: ENDOCRINE SYSTEM (2 MARKS) AND URINARY SYSTEM (1 MARK)
Tasma is enjoying a night out at the pub with her friends. It is well established that alcohol inhibits the secretion of ADH. Explain how this will affect her urine output. (3 marks)
QUESTION 7: GENETICS (3.5 MARKS)
Duchenne muscular dystrophy (DMD) is recessive sex (or X)-linked disorder, which causes muscle degeneration and premature death. A couple is pregnant with a boy and neither has DMD. The father’s family has no history of DMD, but the mother is unsure of her genetic family history as she was adopted. The mother decides to take advantage of some of the new genomic screening tests and learns information about a large number of her genes. She finds that she is a carrier of the DMD-affected allele. (3.5 marks total)
A. What is the mother’s genotype? Explain your reasoning. (1 mark)
B. What is the father’s genotype? Explain your reasoning. (1 mark)
C. Explain why DMD is more common in males than females (1.5 marks)
QUESTION 8: RESPIRATORY (5 MARKS)
Describe the changes in volume and pressure inside the chest cavity during a normal, quiet exhalation.
• Explain why these changes are occurring, and the effect upon airflow. (4 marks)
• Is quiet exhalation an active process? Briefly explain your answer. (1 mark)
QUESTION 9: RESPIRATORY SYSTEM (4 MARKS)
• Complete the below table of partial pressures in external respiration. (2 marks)
pO2 (mmHg) pCO2 (mmHg)
Alveoli
Capillary
• Use to the figures above to explain how differences in partial pressures drive the direction of gas movement between the blood and alveoli. (2 marks)
QUESTION 10: CARDIOVASCULAR SYSTEM (4 MARKS)
A person with type B blood has been involved in a car accident and excessive bleeding necessitates a blood transfusion. Due to an error by a careless laboratory technician, the person is given type A blood. Explain what will happen. (4 marks)
QUESTION 11 : CARDIOVASCULAR (3 MARKS)
To maintain adequate circulation, the average resting heart rate of a healthy non-athletic person is between 60-90 beats/minute. However, a trained athlete’s heart rate is usually about 40 beats/min (sometimes as low as 30 bpm!). Despite this, adequate circulation is maintained in these athletes. Using the terms cardiac output and stroke volume, explain how this is possible. (3 marks)

QUESTION 12: CARDIOVASCULAR (5 MARKS)
• The Wigger’s diagram (below) represents pressure and volume relationships in the left side of the heart during one cardiac cycle. To answer this question, you should focus on the changes in pressure in different chambers of, or vessels leading from, the left side of the heart.
For TWO of the labelled points, state which valve is open/closed at that time. Highlight your chosen point in bold. You must also explain WHY that valve opened/closed and where the blood is flowing immediately after this point in time, due to the change in position of the valve. An example is provided. (4 marks)
Label Valve (name and open/closed) Explanation
A
B
C
D Left AV/bicuspid valve opens The pressure in the left ventricle becomes lower than that in the left atrium. Blood flows from the left atrium to the left ventricle.

• The first heart sound “lub” is associated with which labelled point on the Wigger’s diagram? What creates this sound? (1 mark)
QUESTION 13: CARDIOVASCULAR SYSTEM (2 MARKS)
The below pictures illustrate phases of haemostasis. Choose ONE of the pictures. State which phase of haemostasis is depicted. You must also provide a brief description of your chosen phase. Highlight your chosen row in bold. Note: it is not necessary to label parts of the diagrams, but you may do so if it will help you explain the phases. (2 marks total)
Picture Name of phase Description of phase

QUESTION 14: NERVOUS SYSTEM (5 MARKS)
The following questions relate to the role and importance of a spinal reflex in the body.
• Complete the table below to summarise the FIVE anatomical units of the reflex arc (column 1). Use the patellar reflex to provide an example for the blank anatomical units (column 2).
(3 marks)
Anatomical unit Example (patellar reflex)
1 Receptor
2
3 Integrating centre
4
5
• Using the patellar reflex as an example, explain the purpose of this neural reflex. (2 marks)
QUESTION 15: NERVOUS SYSTEM (1 MARK)
Name the region of the brain responsible for regulation of breathing and blood pressure. Would you expect damage in this region to be fatal? Why? (1 mark)
QUESTION 16: NERVOUS SYSTEM (4 MARKS)
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)

Step Outline
1
2
3
4
QUESTION 17: URINARY SYSTEM (2 MARKS)
List two (2) differences between the external and internal urethral sphincters. The differences must relate to structure, function or innervation of these sphincters. (1 mark/difference; 2 marks total)
QUESTION 18: URINARY SYSTEM (6 MARKS)
• The following table describes the three elementary steps of urine formation. Complete the missing parts of the table. (0.5 marks/cell; 3 marks total)
Step in urine formation Where does this step take place? What happens?
Filtration
Water and/or solutes are transported from the tubular lumen to peritubular capillaries (blood)
Along the length of the tubular network; the exact location depends on the substance being transported
• Glucose and protein (e.g. albumin) are substances normally found in blood. Choose ONE of these molecules and complete the relevant column in the table below. Assume you are discussing what happens in a healthy person. (1 mark per box; 3 marks total)
• Describe what happens to your selected substance at the glomerulus. Explain why/why not the substance will move into the tubule system.
• If the substance moves into the tubule system, describe what happens to the substance along the tubule system. Explain why.
• Do you expect to find this substance in the urine? Explain why or why not.
Glucose Protein
• Glomerulus

• Tubule system

• Urine