Hormones & Homeostasis

Question 1

Endocrine System

Answer 1

ductless system that happens through blood and is the mechanism for hormone transport

Question 2

Characteristics of the Endocrine System

Answer 2

1. Ductless
2. Occurs in blood stream
3. Hormones + hormone shapes are highly specific to a target cell
4. Does not have exocrine glands

Question 3

Exocrine glands

Answer 3

glands that have ducts and release substances out (ie. mammary glands, sweat glands, sebaceous glands)–NOT part of the endocrine system

Question 4

Which hormones does the posterior pituitary control?

Answer 4

ADH (vasopressin) and oxytocin

Question 5

Neurohypophosis

Answer 5

The pathway from the hypothalamus to the posterior pituitary, where hormones ADH and oxytocin are made and then sent out to the rest of the body

Question 6

Function of ADH

Answer 6

Anti-diuretic hormone– causes you to retain water. Released when solute concentrations in the blood are high and signals to the kidneys to open up the aquaporins and let water out of the collecting duct and into surrounding tissue

Question 7

Why does caffeine cause dehydration?

Answer 7

Because caffeine is a competitive inhibitor for ADH and prevents it from opening up aquaporins

Question 8

Which receptors detect blood solute concentration?

Answer 8

Osmoreceptors in the hypothalamus

Question 9

What does the anterior pituitary gland control?

Answer 9

Most other hormones besides oxytoxin + ADH, sends hormones that signal to other glands

Question 10

Hypothalamus

Answer 10

Area of the brain that acts as the control center for hormones, sends signals for the pituitary gland to signal to other secondary glands

Question 11

Homeostasis

Answer 11

the tendency of an organism to maintain a constant internal environment (eg. constant levels of pH or O2)

Question 12

Negative feedback loop

Answer 12

Reaction where the output regulates the production of the output. Basically, the more the output, the more the process is reduced

Found in homeostasis and processes like temperature and glucose regulation

Question 13

Cooling Mechanisms

Answer 13

1. Vasodilation- Capillaries dilate, so blood flow is slower and more heat can be released + capillaries move closer to surface of skin, makes it easier to liberate heat
2. Sweating- evaporative cooling

Question 14

Warming Mechanisms

Answer 14

1. Vasoconstriction- skin arterioles contract, and capillaries move away from surface so less heat is lost
2. Shivering- muscles shake in small movements, which uses up ATP and then the reaction releases heat as byproduct.
3. Piloerection (goosebumps)- traps pockets of heat close to body surface and closes off any holes in skin
4. Behavioral responses- ie. burrowing, putting on clothes, bathing in hot springs, etc

Question 15

Positive Feedback Loops

Answer 15

When the product of a reaction leads to an increase in the reaction

Question 16

Examples of Positive Feedback Loops

Answer 16

1. Oxytocin in labor and contraction
2. Blood clotting- when clotting factors are released, it signals for more platelets to join, and those platelets release clotting factors, so the more platelets, the more clotting factors are released and the reaction keeps building

Question 17

What do B-islet cells produce?

Answer 17

Insulin

Question 18

What do A-islet cells produce?

Answer 18

Glucagon

Question 19

What happens when blood sugar is elevated?

Answer 19

1. Pancreas detects high blood sugar
2. B-islet cells release insulin
3. Insulin signals to liver to take in more glucose and change it into glycogen
4. Insulin also signals to muscles and cells to take up more glucose and remove from the blood

Question 20

What happens when blood sugar is low?

Answer 20

1. Pancreas detects low blood sugar
2. A-islet cells release glucagon
3. Glucagon signals to liver to break down glycogen and release the alpha-D-glu into the blood stream

Question 21

Steroids

Answer 21

hormones made out of lipids and derived from cholesterol

Question 22

How do steroids signal differently from protein hormones?

Answer 22

Steroid hormones go directly through the plasma membrane and interact with intercellular receptors. Protein hormones must bind to the outside and trigger signal transduction and g-protein

Question 23

Examples of steroid hormones

Answer 23

Testosterone, estrogen, cortisol, and progesterone

Question 24

Melatonin

Answer 24

Hormone produced in pineal gland, acts on MT1 and MT2 receptors, which lower body temperature and signal for sleep. Production is inhibited by suprachiasmatic nucleus when it is light

Question 25

Leptin

Answer 25

satiety hormone produced in adipose tissue. the more fat, the more leptin. Responsible for setting metabolism and communicating with hypothalamus to decrease food intake, increase metabolic rate, increase activity level, increase body temperature, and increase inhibition insulin synthesis

Question 26

Ghrelin

Answer 26

hormone that leads to hunger cues, secreted in the fundus of the stomach and antagonistic to leptin

Question 27

Prader-Willi Syndrome

Answer 27

syndrome where ghrelin levels do not decrease after a meal, making them always hungry

Question 28

Thyroid Gland

Answer 28

butterfly shaped gland in front of the trachea, responsible for regulating metabolism

Question 29

Which hormones does the thyroid gland secrete?

Answer 29

Triiodothyronine (T3) and Thyroxin (T4)

Question 30

Thyroxin

Answer 30

hormone synthesized out of iodine, involved with metabolism and body processes

Question 31

Parathyroid Gland

Answer 31

gland found on the back of the thyroid gland that regulates calcium in blood

Question 32

How does the parathyroid regulate calcium?

Answer 32

it releases PTH in response to low calcium levels, which: increases bone resorption (breaking down of bone and releasing the Ca2+) decreases Ca2+ excretion from kidneys increases Ca2+ absorption in gut

Question 33

Examples of protein hormones

Answer 33

Insulin, TSH (thyroid stimulating hormone), growth hormone, etc

Question 34

Growth Hormone (somatotropin)

Answer 34

Protein hormone that is released from anterior pituitary and causes growth in children + adolescents, regulates body fluids, muscle, cartilage, and bone growth, and sugar and metabolism

Question 35

Human Chorionic Gonadotropic Hormone (HCG)

Answer 35

hormone produced by placenta after its implanted in pregnancy, tested for by pregnancy tests. Synthetic version used to build muscle mass in athletes

Question 36

Negative effects of synthetic HCG use

Answer 36

Acromegaly (hands + facial bones grow) Skin becomes coarse + oily Cancer risk increases Enlarged heart and reduced rhythmic ability

Question 37

Gluconeogenesis

Answer 37

the synthesis of glycogen, done by the liver

Question 38

Glycogenolysis

Answer 38

breaking down of glycogen into glucose, triggered by glucagon

Question 39

Islets of Langerhans

Answer 39

specialized cells in the pancreas that release either insulin or glucagon and play a major role in diabetes

Question 40

Type 1 Diabetes

Answer 40

disease where body is incapable of making insulin and has difficulty making glucagon, which prevents proper management of blood sugar

Question 41

Cause of Type 1 Diabetes

Answer 41

potentially an autoimmune response that kills B-islet cells and weakens A-islet cells, which means insulin can't be produced and glucagon can't be produced properly

Question 42

Type 2 Diabetes

Answer 42

late-onset diabetes, caused by a resistance to insulin, cannot be fixed by insulin, must be treated with diet

Question 43

Cause of Type 2 Diabetes

Answer 43

Heavy carb intake for a prolonged period of time overwhelms and overstimulates receptors, so body down-regulates the number of receptors, making it less sensitive to insulin and therefore unable to properly regulate blood sugar

Question 44

Prolactin

Answer 44

hormone released by anterior pituitary gland that is responsible for developing and enlarging mammary glands, and is inhibited by progesterone, which means that milk comes in at the right time after giving birth

Question 45

Oxytocin

Answer 45

hormone produced in hypothalamus in neurosecretory cell, made only in last few weeks of pregnancy and is stimulated into production by baby's head pressing down on cervix