HOMEOSTASIS

Question 1

What is homeostasis?

Answer 1

Homeostasis is the maintenance of internal balance (a “steady” state) even when the external environment changes significantly

Question 2

What is negative feedback?

Answer 2

Negative feedback is a control mechanism that “damps” its stimulus

Question 3

What is an example of negative feedback?

Answer 3

Sweating, which cools the body when the body produces heat, helping return the body to its set point, eliminating the stimulus

Question 4

What is positive feedback?

Answer 4

Positive feedback is a control mechanism that amplifies that stimulus

Question 5

What are peptide hormones?

Answer 5

Peptide hormones are water soluble hormones and are located in receptors in the plasma membrane/on the cell surface and trigger signal transduction

Question 6

What are steroid hormones?

Answer 6

Steroid hormones are lipid soluble hormones and are located in receptors inside the cell nucleus and act as trascription factors , directly affecting gene expression

Question 7

What happens when blood-glucose levels are low?

Answer 7

Alpha cells in the pancreas secrete glucagon, causing the liver to breakdown glycogen and release glucose

Question 8

What happens when blood-glucose levels are high?

Answer 8

Beta cells in the pancrease release insulin, causing either the liver to take up glucose and build glycogen, or other body cells to take up glucose

Question 9

What is type I diabetes?

Answer 9

Type I diabetes is when beta cells in the pancrease don’t function, so no insulin is produced

Question 10

What is type II diabetes?

Answer 10

Insulin is produced by beta cells in the pancreas, however, it cannot enter the body’s cells because they lack the proper insulin receptors

Question 11

Explain the process of thyoid regulation:

Answer 11

Thyroid releasing hormone is secreted by the hypothalamus to increase thyroid hormone levels, causing the anterior pituitary to produce thyroid stimulating hormome which stimulates the hormones release

Question 12

What is the function of the hypothalamus in homeostasis?

Answer 12

The hypothalamus moniters body condition and consists of neurosectretory cells

Question 13

What is the function of the anterior pituitary in homeostasis?

Answer 13

The anterior pituitary secrete tropic hormones in response to hormones by the hypothalamus

Question 14

What hormones do the adrenal medulla produce?

Answer 14

Norepinephrine and epinephrine

Question 15

What hormones do the adrenal cortex produce?

Answer 15

GLucocoorticoids, mineralocorticoids, and sex steroids

Question 16

What are epinephrine’s multiple effects?

Answer 16

1. In liver cells, epinephrine binds to receptor and activates kinase A, which regulates glycogen metabolism by releasing glucose into blood
2. In smooth muscle cells lining blood vessels of skeletal muscles, epinephrine causes vasodilation, increasing blood flow
3. In smooth muscle cells lining blood vessels of intestines, epinephrine causes vasoconstriction, decreasing blood flow

Question 17

What is a regulator?

Answer 17

An animal is a regulator for an environmental variable if it uses internal mechanisms to control internal change in the face of external fluctuation (e.g. river otter whose body temperature is largely independent of its environment)

Question 18

What is a conformer?

Answer 18

An animal is a conformer if it allows its internal conditions to change in accordance with external changes in a particular variable (e.g. largemouth basses whose body warms and cools when the water temperature change)

Question 19

What is an endothermic organism?

Answer 19

An endothermic organism is warmed mostly by heat generated through metabolism and have mechanisms which cool their body. They can maintain a stable body temperature in the face of large environmental fluctuations

Question 20

What is an ectothermic organism?

Answer 20

An ectothermic organism mostly gains heat from external sources and adjust their body temperature via behavioral means. They can tolerate large fluctuations in internal environment

Question 21

What is a poilkilotherm?

Answer 21

A poilkilotherm is an animal whose body temperature varies with the environment (e.g. largemouth bass)

Question 22

What is a homeotherm?

Answer 22

A homeotherm has a relatively constant body temperature (e.g. river otter)

Question 23

Why are all ectotherms not poilkilotherm and all endotherms not homeotherms?

Answer 23

Because there is no fixed relationship between the source of heat and the stability of body temperature

Question 24

What is thermoregulation?

Answer 24

Thermoregulation is the process by which animals maintain their body temperature within a normal range (98.6 degrees in humans)

Question 25

What are the different types of thermoregulation?

Answer 25

1. Insulation
2. Circulatory adaptations
   
   1. Vasocontriction - decreases heat transfer
   2. Vasodilation - increases heat transfer
3. Cooling by evaporative heat loss
4. Behavioral responses
5. Torpor
6. Metabolism changes
   
   1. Thermogenesis - adjust metabolic rates and vary heat production to match changing rates of heat loss
   2. Nonshivering thermogenesis - the process in which mammals release endocrine signals in response to the cold, causing the mitochindria to increase metabolic activity and thus produce heat instead of ATP

Question 26

What is acclimatization?

Answer 26

Acclimatization is an animal’s temporary adjustment to changes in the external environment

Question 27

What is used to quantify energy use?

Answer 27

Metabolic rate, which is the sum of all the energy an animal uses in a given time interval

Question 28

What is basal metabolic rate?

Answer 28

Basal metabolic rate (BMR) is the minimum metabolic rate of a nongrowing endotherm that is at rest, has an empty stomach, and is not experiencing stress; measured at a comfortable temperature range

Question 29

What is standard metabolic rate?

Answer 29

Standard metabolic rate (SMR) is the minimum metaboic rate of fasting, non-stressed ectotherm measured at a specific temperature

Question 30

What influences metabolic rate?

Answer 30

1. Age
2. Size
3. Sex
4. Activity
5. Temperature
6. Nutrition

Question 31

How does size affect metabolic rate?

Answer 31

Metabolic rate remains roughly proportional to body mass

The energy it takes to maintain each gram of body mass is inversely related to size