Biology Assignment 2: Levers, Muscles, and Brain

This is a biology homework assignment focusing on various aspects of human physiology. It includes questions on levers, muscle function, the nervous system, brain injuries, autonomic responses, memory, sensory perception (smell, taste, equilibrium), and hormones. The assignment requires students to describe mechanisms, compare and contrast different systems, and explain physiological processes. It also includes a case study analysis of Phineas Gage's brain injury and its effects.

Assignment 2 – (50 marks)
1. Briefly describe the three categories of levers, an example of each and if each one works
at an advantage or disadvantage. (3 marks)
2. Name and describe the locations and actions of the muscles typically used in breathing.
(4 marks)
3. Briefly answer to the following questions: (4 marks)
a. Describe four ways drugs can modify the effects of neurotransmitters.
b. Describe the three ways neurotransmitters can be removed.
c. Describe the two conditions that allow maintenance of the resting membrane
potential in excitable cells.
d. Briefly describe what causes the depolarizing phase.
4. Answer to the following questions:
a. Describe the gross external anatomy of the spinal cord. (3 marks)
b. Identify the components of a spinal reflex arc, and describe the function of
each. (3 marks)
5. In 1848, a railroad worker named Phineas Gage was seriously injured during an
explosion on the job. A tapered metal rod ranging from 0.25 inches to 1.25 inches in
diameter and over 3 feet long entered his skull just under his left cheek bone and exited
through the top of his skull. The rod was found over twenty feet away. Amazingly, Gage
lived even though he suffered massive damage to the left front of his brain. His
personality and intellectual abilities changed, however. Before the accident, he was
respected as a smart, capable and even-tempered man. After the accident, he was foul-
mouthed and bad-tempered and could not make up his mind. In the years immediately
preceding his death, he began to have epileptic seizures. Explain the changes observed
in Mr. Gage based on your knowledge of the brain. (4 marks)

6. Answer to the following questions:
a. A patient with chronic skeletal muscle spasms was placed on an anticholinergic
medication. The muscle spasms have gone, but now the patient also reports a
loss of muscle strength. In addition, the patient’s blood pressure is so low that
she faints if she stands up too quickly. Explain the effects of the medication the
patient received. (3 marks)
b. Compare and contrast the overall responses of the sympathetic and
parasympathetic divisions. (4 marks)
7. Answer to the following questions:
a. Describe the role of the reticular activating system in sleep, arousal, and
consciousness. (2 marks)
b. Compare short-term memory vs. long-term memory with regard to specific
changes that are thought to occur in the brain. (2 marks)
8. Answer to the following questions:
a. Explain the process by which smell sensations are sensed and perceived.
(5 marks)
b. Emily was very ill with an upper respiratory infection. Her roommate gave her
some chicken soup to make her feel better. Neither Emily nor her roommate
realized that the soup was too hot to eat until after Emily put a spoonful in her
mouth. Now Emily says she can’t taste anything. Why? When will she be able
to taste again? (3 marks)
c. Differentiate between static and dynamic equilibrium. Describe the structures
and physiological mechanisms involved in receiving and transducing vestibular
sensations. (3 marks)
9. Answer to the following questions:
a. Compare and contrast the mechanisms of action of lipid-soluble vs. water-
soluble hormones. (3 marks)
b. Describe the role of the hypothalamus in the regulation of the pituitary gland.
(2 marks)
10. Enuresis, or bedwetting, may be caused by psychological, anatomical or physiological
factors. In the latter case, vasopressin is often prescribed and is a very effective
treatment. What is vasopressin? How can it prevent enuresis? (2 marks)