Unit 6 Physiology 3 Benchmark

Vanessa Yang
Smith
Period 6 Biology HP
17 March 2014
Biology Study Guide: Unit 6 Physiology III Benchmark
1. Homeostasis maintains and keeps a balance of an organism’s internal environment.
2. The body maintains homeostasis by the feedback inhibition, in which a stimulus produces a response that opposes the original stimulus.
3. The axon terminal is the nerve ending. The nodes speed up the message. The myelin sheath is an insulating membrane. The axon carries impulses away from the cell body. The cell body is the largest part of a typical neuron. The dendrites carry impulses from the environment or from other neurons toward the cell body. The nucleus is the control center of the cell.

4. A synapse is location at which a
neuron can transfer an impulse to another cell.
5. A neurotransmitter is a chemical used by a neuron to transmit an impulse across a synapse to another cell.
6.
When an impulse arrives at an axon terminal, the vesicles release the neurotransmitters into the synaptic cleft. The neurotransmitter molecules diffuse across the synaptic cleft and attach themselves to receptors on the membrane of the neighboring cell. This stimulus causes positive sodium ions to rush across the cell membrane, stimulating the second cell. If the stimulation exceeds the cell’s threshold, a new impulse begins.
7. The autonomic nervous system regulates activities that are involuntary.
8. I don’t know. I’m really tired. Maybe.
9. The hypothalamus is the brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature. The pons is the region in the brain stem that regulates flow of information between the brain and the rest of the body. The cerebellum is the region of the brain that coordinates body movements. The cerebrum is the area of the brain responsible for all voluntary activities of the body.
10. The skin, lungs, liver, kidneys, bladder, and large intestines are in charge of waste removal.
11. When a neuron is resting, the outside of the cell has a net positive charge, and the inside of the cell has a net negative
charge.
12. At the leading edge of the impulse, gates in the sodium channels open. The membrane becomes more permeable to Na+ ions, and an action potential occurs. As the action potential passes, gates in the potassium channels open, allowing K+ ions to flow out and restoring negative potential inside the axon.
13.
Sensory receptors are neurons that react to a specific stimulus such as light or sound by sending impulses to other neurons, and eventually to the central nervous system.
14. Three sensory receptors found in the skin are pain receptors, thermoreceptors, and mechanoreceptors.
15. The parathyroid glands act to maintain homeostasis of calcium levels in the blood.
16. Insulin and glucagon help to keep the level of glucose in the blood stable. Insulin stimulates cells in the liver and muscles to remove sugar from the blood and store it as glycogen or fat. Glucagon stimulates the liver to break down glycogen and release glucose back into the blood. It also stimulates the release of fatty acids from stored fats.
17. The sodium-potassium pump in the neuron cell membrane uses the energy of ATP to pump Na+ out of the cell and, at the same time to pump K+ in.
18. The sensory division of the peripheral nervous system transmits impulses from sense organs to the central nervous system. The motor division transmits impulses from the central nervous system to the muscles or glands.
19. The nerve impulses are electrical current
signals.
20. The sensory neurons carry impulses from the sense organs to the spinal cord and brain. Motor neurons carry impulses from the brain and the spinal cord to muscles and glands. Interneurons connect sensory and motor neurons and carry impulses between them.
21. The pathway that an impulse travels from your foot back to your leg is known as a reflex arc. A sensory neuron communicates directly with a motor neuron.
22. Because they are lipids, steroid hormones can cross cell membranes easily, passing directly into the cytoplasm and even into the nuclei of target cells. Nonsteroid hormones generally cannot pass through the cell membrane of their target cells.
23. Insulin stimulates cells in the liver and muscles to remove sugar from the blood and store it as glycogen or fat.
24. Sure, not really. I don’t like memorizing stuff. But I guess I will.
25. Totally. I will and shall memorize that.
26. The thyroid gland controls your metabolic rate.
27. The liver is the large organ just above the stomach that produces bile.
28. The large intestine is the organ that removes water from the undigested materials that pass through it.
29. The pancreas is the gland that produces hormones that regulate blood sugar, produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acid, and produces sodium bicarbonate.
30. The epiglottis closes over the opening to the trachea to prevent food from blocking the air passageways to the lungs.
31. The rectum is the passageway that waste material is eliminated from the body.
32. The appendix is a vestigial structure that has no function in humans and could cause serious harm if it bursts in the body.
33. Yes. I’m just too good.
34. The kidneys remove urea, excess water, and other waste products from the blood.
35. The glomerulus and the Bowman’s capsule are the filtering units within the kidney.
36. The kidneys produce urea when amino acids are broken down.
37. The ureter is the tube that carries urine to the urinary bladder, while the urethra is the tube that releases the urine from the urinary bladder.
38. The urinary bladder is the saclike organ n which urine is stored before being excreted.
39. The thyroid glands regulate the rate of metabolism.
40. The myelin sheath surrounds a single long axon that leaves many nodes where the axon membrane is exposed. As the impulse moves along the axon, it jumps from one node to the next, which increases the speed at which the impulse can travel.