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IB Biology HL > Hormones & Homeostasis > Flashcards

Hormones & Homeostasis Flashcards

1
Q

Endocrine System

A

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

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2
Q

Characteristics of the Endocrine System

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

Exocrine glands

A

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

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4
Q

Which hormones does the posterior pituitary control?

A

ADH (vasopressin) and oxytocin

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5
Q

Neurohypophosis

A

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

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6
Q

Function of ADH

A

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

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7
Q

Why does caffeine cause dehydration?

A

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

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8
Q

Which receptors detect blood solute concentration?

A

Osmoreceptors in the hypothalamus

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9
Q

What does the anterior pituitary gland control?

A

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

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10
Q

Hypothalamus

A

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

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11
Q

Homeostasis

A

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

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12
Q

Negative feedback loop

A

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

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13
Q

Cooling Mechanisms

A
  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
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14
Q

Warming Mechanisms

A
  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
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15
Q

Positive Feedback Loops

A

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

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16
Q

Examples of Positive Feedback Loops

A
  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
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17
Q

What do B-islet cells produce?

A

Insulin

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18
Q

What do A-islet cells produce?

A

Glucagon

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19
Q

What happens when blood sugar is elevated?

A
  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
20
Q

What happens when blood sugar is low?

A
  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
21
Q

Steroids

A

hormones made out of lipids and derived from cholesterol

22
Q

How do steroids signal differently from protein hormones?

A

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

23
Q

Examples of steroid hormones

A

Testosterone, estrogen, cortisol, and progesterone

24
Q

Melatonin

A

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

25
Q

Leptin

A

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

26
Q

Ghrelin

A

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

27
Q

Prader-Willi Syndrome

A

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

28
Q

Thyroid Gland

A

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

29
Q

Which hormones does the thyroid gland secrete?

A

Triiodothyronine (T3) and Thyroxin (T4)

30
Q

Thyroxin

A

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

31
Q

Parathyroid Gland

A

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

32
Q

How does the parathyroid regulate calcium?

A

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

33
Q

Examples of protein hormones

A

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

34
Q

Growth Hormone (somatotropin)

A

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

35
Q

Human Chorionic Gonadotropic Hormone (HCG)

A

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

36
Q

Negative effects of synthetic HCG use

A

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

37
Q

Gluconeogenesis

A

the synthesis of glycogen, done by the liver

38
Q

Glycogenolysis

A

breaking down of glycogen into glucose, triggered by glucagon

39
Q

Islets of Langerhans

A

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

40
Q

Type 1 Diabetes

A

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

41
Q

Cause of Type 1 Diabetes

A

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

42
Q

Type 2 Diabetes

A

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

43
Q

Cause of Type 2 Diabetes

A

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

44
Q

Prolactin

A

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

45
Q

Oxytocin

A

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

IB Biology HL (12 decks)

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