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Kasia Hirniak, Emily Colangelo and Ezgi Cetinkaya

SBI4U Homeostasis Unit Test

Name: _______________________________ Date: _______________________

Instructions: You have 70 minutes to complete all test questions in the space provided.

A. Fill in the blank questions: (12 marks) – 9 minutes

1. _______________ breaks down neurotransmitters within the synapse so that the postsynaptic receptors are available for the next signal. Acetycholinesterase K/U

2. _____________ are located at one end of a neuron, they are the primary site for receiving signals from other neurons. Dendrites (K/U)

3. ___________________ is a primary neurotransmitter of the sympathetic nervous system which increases heart rate, blood pressure, and produces other “fight-or-flight” responses. Norepinephrine (K/U)

4. _____________________ are neurons located in the CNS. Interneurons (K/U)

5. During __________________ there is a facilitated diffusion of sodium ions, whereas during ________________there is a facilitated diffusion of potassium ions, of the action potential. Depolarization, Repolarization K/U

6. Molecules called _______________________ relay messages across the synaptic cleft between the two neurons. Neurotransmitters (K/U)

7. ___________________increase the speed at which action potentials travel and provide insulation to the axon. Myelin sheath (K/U)

8. Stress tends to promote _____________ activity of the sympathetic nervous system and secretion of epinephrine thereby ____________ gluconeogenesis. (T/I) increased, stimulating


9. Increased glucagon secretion will stimulate the liver to ___________________ gluconeogenesis and glycogenolysis which ultimately works to _______________ plasma glucose levels. (T/I) increase, increase

B. Multiple-Choice questions: (21 marks) K/U – 21 minutesUse the diagram to your right to answer questions 1-3.1. Which structure produces secretions that regulate E and H?a) Ab) Bc) Cd) D

2. Which two structures secrete substances that control the menstrual cycle?a) A and Fb) B and Hc) C and Dd) E and I

3. Which letter indicates the organ that produces insulin and glucagon?a) Hb) Gc) Bd) F

4. The function of the urinary system is to maintain a blood pH of approximatelya) 7.1b) 6.9c) 7.2d) 7.3

5. The continuous production of metabolic wastes establishes a steep concentration gradient across the plasma membrane causing wastes to diffuse out of cells and into the ___________________.a) intracellular fluidb) extracellular fluidc) interstitial fluidd) both b and c

6. The drainage of the urinary bladder is controlled by:a) sphinctersb) urethra


c) uretersd) the cortex

7. ____________________ is produced in the liver from the breakdown of excess amino acids that are the building blocks of proteinsa) Uretersb) EPOc) NH2d) Urea

8. Each kidney is composed of _________ to ____________ nephronsa) one thousand to two thousandb) two thousand to three thousandc) one million to two milliond) two million to three million

9. In the nephron, as the water concentration in the filtrate _____________, the chloride ion concentration in the filtrate ______________.a) decreases, increasesb) increases, decreasesc) decreases, decreasesd) increases, increases

10. ________________ is secreted by the anterior pituitary gland and increases the permeability of the distal tubule and collecting ducta) EPOb) ADHc) LHd) Testosterone

11. A human skeleton is shown in the photograph. The elongation of structures A and B was stimulated by a hormone produced by the

a) islets of Langerhansb) liverc) pituitary glandd) adrenal gland


12. The primary endocrine organs include the following….a) Hypothalamus, liver, adrenal cortexb) Hypothalamus, liver, small intestinec) Hypothalamus, pineal gland, adrenal cortexd) Hypothalamus, GI tract, adrenal cortex

12. The anterior pituitary gland is known to secret the following hormones…a) Luteinizing hormone (LH), follicle stimulating hormone (FSH),

prolactinb) Lipid hormone (LH), follicle stimulating hormone (FSH),

prolactinc) Parathyroid hormone (PTH), follicle stimulating hormone

(FSH), prolactind) Antidiuretic hormone (ADH), follicle stimulating hormone

(FSH), prolactin

13. The hormone oxytocin…a) Is secreted by the hypothalamus and stimulates uterine

contractions and milk ejection by mammary glands in females b) Is secreted by the hypothalamus and has an unknown

function in malesc) Is secreted by the posterior pituitary gland and stimulates

uterine contractions and milk ejection by mammary glands in females

d) Is secreted by the parathyroid glands and stimulates uterine contractions and milk ejection by mammary glands in females

14. The hypothalamus is connected to the posterior pituitary gland by which of the followinga) Infundibulum b) Capillary bedc) Anterior pituitaryd) Paraventricular nucleus

15. Calcitriol (or vitamin D3) is produced in the sin and kidneys. It’s main function is to a) Promote secretion of acid by intestine


b) Promotes absorption of calcium by intestinec) Inhibits absorption of calcium by intestined) Inhibits secretion of acid by intestine

16. The adrenal cortex secretes a number of hormones all referred to as adrenocorticoids. These include the following a) Sex-corticoids, mineralocorticoids, and glucocorticoidsb) Sex hormones, mineralocorticoids, and glucocorticoidsc) Catecholamines, mineralocorticoids, and glucocorticoidsd) Catecholamines, sex-corticoids, and glucocorticoids

17. Excess thyroid hormones in the blood a) Induce strong positive feedback, thereby decreasing TRH and

TSH release into the blood b) Induce strong positive feedback, thereby increasing TRH and

TSH release into the bloodc) Induce strong negative feedback, thereby increasing TRH and

TSH release into the bloodd) Induce strong negative feedback, thereby decreasing TRH and

TSH release into the blood

18. Thyrotropin releasing hormone (TRH) is known to a) Inhibit the release of TSH from the posterior pituitaryb) Stimulate the release of TSH from the posterior pituitary c) Stimulate the release of TSH from the anterior pituitaryd) Inhibit the release of TSH from the anterior pituitary

19. Tropic hormones of the hypothalamus and anterior pituitary include the followinga) Prolactin releasing hormone (PRH), prolactin inhibiting

hormone (PIH), and growth hormone releasing hormone (GHRH)

b) Prolactin releasing hormone (PRH), thyrotropin releasing hormone (TRH), and growth hormone releasing hormone (GHRH)

c) Prolactin releasing hormone (PRH), thyroid stimulating hormone (TSH), and growth hormone releasing hormone (GHRH)

d) Prolactin releasing hormone (PRH), tetraiodothyronine (T4), and growth hormone releasing hormone (GHRH)


20. The secondary endocrine organs include the followinga) Heart, kidneys, thymus, liver, and skinb) Heart, kidneys, digestive organs, liver, and skinc) Heart, kidneys, ovaries, organs, liver, and skind) Heart, kidneys, parathyroid glands, liver, and skin

C. Matching (6 marks) K/U – 6 minutes

Column A Column Bi. Synaptic cleft (c) a. Carries information about the

environment to the brainii. Sympathetic

Nervous System (d)

b. Involved in processing of somatic sensory and motor information

iii. Refractory period (f)

c. A junction between two neurons

iv. Cerebrum (b) d. Associated with the “flight or fight” response

v. Sensory neuron (a) e. Supports the brain, cushions delicate brain structures and helps to transport nutrients and waste products

vi. Cerebrospinal fluid (e)

f. The time required before another action potential can be produced

Match the following words to the diagram below (8 marks) K/U – 8 minutes

Thymus (6)Parathyroid glands (1) Ovaries (female) (8)Pituitary gland (5) Adrenal glands (3) Pancreas (7)Testis (4)Thyroid glands (2)


D. Short answer questions: 1. Explain how nerve impulses travel faster along axons covered by myelin sheath than they do along non-myelinated neurons. Ensure to support your answer with a detailed diagram (3 marks) K/U – 3 minutes

The 3 stages of an action potential only take place at the Nodes of Ranvier and then the action potential slides through the myelinated portion of an axon thus increasing its propagation time.In non-myelinated axons the action potential stages take


place through the whole axon thus taking more time to reach the next neuron.

2. Hassan visited his psychiatrist and was told that his serotonin levels are low. His doctor explained to him that serotonin is a naturally occurring neurotransmitter that affects individual’s emotions and their moods. A lack of serotonin has been associated with conditions such as phobias, schizophrenia, depression, and aggressive behaviors. The doctor showed him a chart with some of the drugs that might affect his serotonin levels.

Drug EffectHallucinogens (LSD, ecstasy) React directly with the serotonin receptors to

produce the same effect of serotonin

Clozapine Prevents serotonin from binding to the postsynaptic membranes

Prozac, Zoloft, Paxil Cause serotonin to remain longer in the brain

a) Why is Prozac prescribed for people with depression? (2 marks) A – 2 minutes

Prozac increases serotonin levels in the brain what results in a more positive mood.

b) Which drug should not be prescribed by someone experiencing depression? (2 marks) A – 1 minute

Clozapine

3. Aside from filtering blood to remove wastes, what are the other functions of the kidneys? (7 marks) K/U – 5 minutesIn addition to filtering blood to remove toxic waste products, the kidneys also control water balance, pH, and levels of sodium, potassium, bicarbonate, and calcium ions in the blood. They also


secrete the hormone EPO that stimulates red blood cell production and activates vitamin D production in the skin.

4. List the organs that compose the urinary system (4 marks) K/U – 2 minutes

– two kidneys,– two ureters,– one urinary bladder and– one urethra.

5. Diabetes mellitus is known to affect around 4-6% of the adult population and is the 7th leading cause of death in the United States. Are both forms (both insulin dependent and non-insulin dependent) caused by persistent hypoglycemia or hyperglycemia? Expand on your answer by explaining how or where the system breaks down. (5 marks) A – 5 minutes

Level 4 Answer- Student not only states that it is hyperglycemia but also clearly explains exactly how the system breaks down to cause this condition.

The primary sign of either form is hyperglycemia. This is due to reduced insulin activity which is caused in part by reduced glucose uptake and utilization by many tissues, as well as increased glucose output by the liver. The increased glucose output is caused by increased gluconeogenesis and glycogenolysis and reduced glycogen synthesis. Glucagon secretion is usually elevated because the glucose permeability of alpha cells in the pancreas (which secretes glucagon) is insulin dependent. This lack of insulin slows down the ability of glucose to enter these cells, which makes them behave as if the glucose level is lower than it actually is.

6. Hyposecretion of cortisol is also known as Addison’s disease.

Explain how this disease is caused by relating it to feedback loops discussed in class. (5 marks) A – 5 minutes

Level 4 answer: Student should be able to clearly explain the process of the way in which all the hormones and organs are involved. They may draw feedback loops to show the process more clearly.

Addison’s disease is characterized by hypoglycemia and poor tolerance of stress. It is usually a result of destruction of the


adrenal cortex and so there is a defect in the secretion of aldosterone. Aldosterone normally promotes sodium retention and potassium secretion by the kidneys. Addison’s disease therefore involves having excess sodium secretion and potassium retention, which by altering plasma sodium and plasma levels results in cardiac arrhythmias and other neuromuscular signs.

E. Labeling: 1. Please CLEARLY label on the diagram below the following structures (3 marks) K/U - 3 minutes-Cortex-Medulla-Pelvis

Cortex

Pelvis

Medulla

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