Worksheet on Function of a Variety of Cells Throughout the Body
Fill in the blank boxes to complete TWO rows of your choice in the following table, which summarises the name, location, and function of a variety of cells throughout the body. The first line is completed as an example of the level of detail required. Only the first TWO rows completed will be marked (1 mark/row; 2 marks total)
|Cell name||Where would you usually expect to find this cell type?||What is its job (or primary role)?|
|Melanocyte||In the deep layer of the stratified squamous epithelium of the skin.||Production of melanin to protect underlying tissue from harmful UV radiation.|
|Spontaneously depolarise to trigger contraction of cardiac muscle. Establishes the heart rate.|
|Schwann cell||This cell is found in the peripheral nervous system which is around the nerves of the extremities of the body.||The most significant function of the Schwann cell is to myelinate the axons of the peripheral nervous system.|
|Maintain the protein and mineral content of the surrounding bone matrix.|
|Non-specific immune surveillance of peripheral tissues (recognizing and destroying abnormal cells).|
|Contains large quantities of haemoglobin, enabling it to bind and transport respiratory gases.|
|Parathyroid chief cells||The parathyroid chief cells are located in the parathyroid glands.||The main role of the parathyroid chief cells is the maintenance of the calcium homeostasis. |
Name the personal protective equipment that should be worn when handling someone else’s urine, and explain why those items are needed. (2 marks)
The personal protective equipment that must be worn while handling someone else’s urine are gloves, gowns as well as masks. These items are needed and must be worn in order to protect ourselves from the harmful germs and also from the disease-causing organisms. By wearing such equipment the individual can protect themselves from the transmission of the infectious diseases.
Complete the table to compare how the following cells carry out the third line of defence:
- Cytotoxic T-lymphocytes
Some sections are completed for you to help guide your answers. (0.5 marks/box; 4 marks total)
|Overall role||Produce antibodies||At the time of role in the disease pathogenesis, it produces antiviral cytokines which are capable of purging HBV from the viable hepatocytes where the Cytotoxic T-cells aid in eliminating the virus.|
|Target||B-lymphocytes mediate the humoral or the antibody-mediated immunity and it produces an antibody that is directed against the invaded pathogens. The naive B-cells used to bind with the antigens on the circulation of the B cell receptors present on the surface.||Antigen-bearing host cells recognized as ‘foreign’; e.g., cancer cells, virus-infected cells, or cells with intracellular bacteria|
|Facilitated by which helper cell?||B-lymphocytes facilitated by Helper T-cells ||It is also facilitated by Helper T-cells.|
|Is this specific immunity? |
(yes or no)
|These cells function in the humoral immunity of the adaptive immune system by secreting antibodies. ||Most of the Cytotoxic T-cells used to express the T-cell receptors which help in recognizing a specific antigen.|
|What cells provide long-term immunity?||This cell provides long-term immunity.||It is basically involved in the cell-mediated immune response. |
The following paragraph refers to muscle contraction. Fill in each of the blanks to complete the paragraph using terms from the list provided. More terms than necessary are provided, and terms may be used more than once. (0.5 marks each; total 3 marks)
The action potential spreads along the Sarcolemma until it reaches a T-tubule. The action potential continues down the T-tubule, where it triggers the release of Ca++ ions from the sarcoplasmic reticulum. This exposes binding sites on Actin. Myosin Heads bind to the exposed sites on Actin to form cross-bridges.
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)
The calcium homeostasis is described as the regulation of the concentration of the calcium ions in the extracellular fluid. The PTH hormone which is secreted from the parathyroid glands helps in the regulation of the blood calcium levels. Moreover, the PTH hormone helps in increases the blood calcium levels by stimulating the osteoclasts that break down bones in order to release calcium into the bloodstream. Furthermore, Calcitonin is a hormone that is produced by thyroid which acts in the opposition of PTH by inhibiting osteoclasts and stimulating osteoblasts which assist in increasing the excretion of calcium into the urine through the help of kidneys. In addition, the role of osteoblast is that it helps in the formation of bones.
Describe how the hypothalamus controls the release of hormones from the:
- anterior lobe of the pituitary gland
- posterior lobe of the pituitary gland
In your answer, give specific examples and clearly name any hormones involved. (2 marks/lobe)
- The hormones of the pituitary gland used to send signals to the other endocrine glands in order to stimulate or inhibit their own hormone production. The anterior lobe of the pituitary gland releases hormones through receiving releasing or the inhibiting hormones from the hypothalamus. Hence, these hypothalamic hormones send signals to the anterior lobe of the pituitary gland whether to release hormones or to stop the production of it.
- The posterior lobe of the pituitary glands consists of the end of the nerve cells which is coming from the hypothalamus. Therefore, the hypothalamus used to sends hormones directly to the posterior lobe of the pituitary gland through these nerves and then the pituitary gland release those hormones.
Duchenne muscular dystrophy (DMD) is a recessive sex-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 marks total)
1. What is the mother’s genotype? Explain your reasoning. (1 mark)
The mother’s genotype is XX as the mother consists of the two sex-linked genes.
2. What is the father’s genotype? Explain your reasoning. (1 mark)
The father’s genotype is XY as the father consists of only one sex-linked gene.
3. What is the likelihood of the male fetus having DMD? Use a Punnett square to explain your answer. (1 mark)
Let the healthy copy of the gene is represented as XB and the damaged one is represented as Xb.
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)
The mechanism of the breathing follows the Boyle’s law that states that the pressure, as well as volume, possesses an inverse relationship. The process of the inhalation occurs due to the rise in the lung volume that results in the decrease in the pressure in the lungs as compared to the atmosphere and hence the air rushes in the air passage. Similarly, the process of exhalation occurs because of the elastic recoil of the tissues of lungs that causes a reduction in the volume results in a rise in pressure as compared to the atmosphere and therefore air rushes out from the lungs. '
Regarding quiet ventilation, which process is active — inhalation or exhalation? Briefly explain your answer. (1 mark)
During quiet ventilation, inhalation occurs as the air moves from the atmosphere into the lungs which are also known as the tidal volume and is referred to as VT that is of 500 millilitres.
The graph below displays the oxygen dissociation curve and factors that affect the release of oxygen from haemoglobin (Hb). Explain how these factors will affect the release of oxygen into the blood supply of a hard-working skeletal muscle. (3 marks)
The hard-working skeletal muscle or the exercise causes a rise in temperature, acidity as well as metabolic intermediates and the decrease in the oxygen in the muscle tissues. Hence this leads to a rise in the dissociation of oxygen from the blood flowing through the muscles by supplying them with much-required oxygen. Furthermore, the body increases blood flow to the muscles in order to supply them with more oxygen. In addition the warming up before the exercise aid in prime the muscles to gather ample oxygen by kick-starting metabolism as well as in the increase in temperature.
Choose ONE of the blood types below and answer the following questions. Only the FIRST completed column will be marked
- State the type of antigens found on the surface of those red blood cells, and the type of antibodies found in the plasma of a person with the blood type shown. Type your answer in the table below (1 mark total)
- Could a person with your chosen blood type safely receive type AB blood via transfusion? Explain your answer below. (2 marks)
The group O blood types do not possess any type of antigens like antigen-A and antigen-B so they can safely receive plasma from any blood group types. However, O positive can receive blood from O positive and negative and O negative will only receive from O negative blood group.
|Red blood cell type|
|Antigens on red blood cells||It does not contain any A or B antigens of the ABO blood system|
|Antibodies in plasma||Anti-A and Anti-B antibodies are found in the plasma.|
Why is an injury to the medulla oblongata usually fatal? (2 marks)
The injury to the medulla oblongata is basically fatal because it is the portion of the hindbrain which generally controls the autonomic functions like digestion, breathing, heart, and functioning of the blood vessels, sneezing as well as swallowing. Apart from this, the medulla oblongata helps in transferring messages to various parts of the body from the brain to the spinal cord. Therefore, the injury of medulla oblongata will lead to severe damage in the body of the individuals.
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 the heart||No parasympathetic innervation of the ventricular myocardium; therefore, no result|
|Airways in the lungs||It causes bronchodilation in the airways passage of the lungs.||It causes bronchoconstriction in the air passage of the lungs.|
|Pupil||It causes dilation of the pupil due to the adrenergic receptors which cause the contraction of the radial muscles.||The sphincter is innervated by this stimulation in the pupil.|
The paragraph below relates to this graph, which describes changes in membrane potential over time.
1. Fill in each of the blanks to complete the paragraph using terms from the list provided. More words than necessary are provided, and terms may be used more than once. (0.5 marks each; 3.5 marks total)
During repolarization, the resting membrane potentialof the cell is 70 mV more negative than the outside of the cell. When a stimulus is applied, the membrane potential must reach +35 mV in order for an Action Potential to be fired. At the start of an Action Potential, Na+ channels open and Na+ ionsenter the cell. This phase is called depolarization.
The relative refractory period is the period of time in which the nerve membrane can start another action potential only if a much greater stimulus than usual is applied.
2. Referring to the graph above, at which numbered point do potassium gates begin to open? (0.5 marks)
The potassium gates begin to open at +30mV that is at the point numbered as 5.
Antidiuretic hormone and aldosterone influence water and electrolyte balance of the body. The following table summarises the main characteristics of these hormones; your task is to fill in the empty cells in the table. (0.5 marks/box; 4 marks total)
|Where is this hormone synthesized?||The ADH is synthesized through the neurons in the supraoptic nucleus of the hypothalamus.||Aldosterone which is considered to be as the mineralocorticoid hormone is basically a steroid hormone which is synthesized from zona glomerulosa of the adrenal cortex in the adrenal gland. |
|Which gland secretes this hormone?||It is secreted by the pituitary gland.||It is secreted by the adrenal glands.|
|Primary effect?||The primary effect of ADH is the water retention by kidneys.||The primary effect of the aldosterone hormone is the occurrence of the primary hyperaldosteronism in which the symptoms consist of low BP of potassium, high BP and an abnormal rise in blood volume.|
Mechanism of action
(How does it work?)
|ADH continuously helps in regulating as well as balancing the amount of water in the blood. ||This hormone basically acts in the functional unit of the kidneys so as to help in the conservation sodium, retention of the water in order to stabilize the BP and secretion of potassium.|
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||It takes place in the renal corpuscle.|
Basically, it uses to filters about 20% of the plasma volume that is passing through the glomerulus at any duration of time. Hence the entire plasma volume is filtered sixty times a day.
|Re-absorption||It takes place largely in the proximal tubules.||Water and/or solutes are transported from the tubular lumen to peritubular capillaries (blood)|
|secretion||Along the length of the tubular network; the exact location depends on the substance being transported||It helps the capability of the kidneys to eliminate certain toxins as well as wastes from the body.|
List two (2) differences between the external and internal urethral sphincters. The differences must relate to structure, function or innervation of these sphincters. (0.5 marks/difference; 1 mark total)
The differences between the internal as well as external urethral sphincter are that the internal sphincter is the thickened area of the bladder urethra junction. It is basically formed by smooth muscles and is involuntary in nature whereas the external sphincter is made up of skeletal muscles and is voluntary in nature.
Explain how baroreceptors contribute to control blood pressure during a short period of widespread vasodilation. (3 marks)
The baroreceptors are referred to as the pressure sensing bodies and it is also known as stretch receptors. However, these receptors are sensitive to the rapid offsets in the blood pressures and it is located in the arch of the aorta as well as in the carotid sinus. During the rapid offsets of the blood pressure a large volume of the blood is shifted from the peripheral to the central region of the body and hence a large volume of blood enters into the heart which leads to the increase in preload causes the heart to rise in the cardiac output. Therefore, this rise in blood pressure is registered by the baroreceptors. Consequently, a drop in blood pressure is also registered by baroreceptors when the individual stands up suddenly from sitting position. The high blood pressure in the blood vessels causes the stretch of these baroreceptors that result in the movement of the Na+ ions into the nerve endings which leads to an initiating of the action potential. Moreover, these baroreceptors possess baseline firing pattern it means they possess the intrinsic potential for generating the action potentials at the particular frequency at all times.
Name four (4) major vessels attached to the heart, and explain where they receive blood from, and where they carry blood to (4 marks)
|Major vessel||Receives blood from||Carries blood to|
|Aorta||Receives blood from the left ventricle through the aortic valve.||It carries oxygenated blood from the heart to the rest of the body.|
|Vena Cava||It drains blood from every single vein in the body.||The inferior vena cava carries deoxygenated blood from the lower half of the body to the right atrium of the heart whereas the superior vena cava carries oxygenated blood to the rest of the body parts.|
|Pulmonary artery ||It receives blood from the heart ||Carries to the lungs.|
|Pulmonary vein||It receives oxygenated blood from the lungs ||Carries to the heart.|
Explain the term ‘normal sinus rhythm’. (1 mark)
The normal sinus rhythm is referred to as the normal heartbeat with respect to the rhythm and heartbeat. In this condition, the heart rate falls between 60 to 100 beats per minute. QUESTION 21
Complete the table on the heart valves below by briefly explaining the function of each and stating when each set of valves is closed. (0.5 per box; 2 marks total)
|Type of heart valve||What is their function?||When are the valves closed?|
|Semilunar valves||The main function of these valves is to prevent the pulmonary and the aortic valves to alter the directions to the interior of the ventricles thereby impeding the flow of the blood to return back to the ventricles.||With the begin of the diastole, ventricles begin to relax and the pressure within the pulmonary artery and aorta exceeds the ventricular pressure leads to the close of the semilunar valves. |
|Atrioventricular (AV) valves||It helps in separating the atria from ventricles but prevents the flow in the opposite direction. ||It closes when the ventricles begin to contract and hence the ventricular pressure exceeds the atrial pressure causing the valves to get closed.|