Hormones Flashcards

1
Q

What are a pro and a con of hormones?

A

Pro - spread all over the place

Con - move by diffusion which is slow

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2
Q

Which glands secrete hormones?

A

Endocrine Glands

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3
Q

What is a Neural Signal?

A

Facilitated by the neurotransmitter, only between two neurons.

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4
Q

What are Neuroendocrine Signals?

A

Facilitated by Neurohormones which are hormones released by neurons.

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5
Q

What are Endocrine Signals?

A

hormones carried between cells by blood/body fluids

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6
Q

What are Paracrine Signals?

A

just look at the photo 🦧

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7
Q

What are Autoncrine Signals?

A

It’s that easy🍌

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8
Q

What are the three Hormone Pathways?

A
  1. The Endocrine Pathway
  2. Neuroendocrine Pathway
  3. Neuroendocrine-to-endocrine Pathway
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9
Q

What is the order in the Endocrine Pathway? (5)

A
  1. Stimulus -> Endocrine Cell
  2. Cell -> Hormone
  3. Hormone -> Effector Cell
  4. Effector Cell -> Response
  5. Feedback Inhibition -> Endocrine Cell
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10
Q

What is the order in the Neuroendocrine Pathway? (7)

A
  1. Stimulus -> Sensory Cell
  2. Sensory Cell -> Neurotransmitters
  3. Neurotransmitters -> CNS
  4. CNS -> Neurohormone
  5. Neurohormone -> Effector Cell
  6. Effector Cell -> Response
  7. Feedback Inhibition -> CNS +Sensory Cell
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11
Q

What is the order in the Neuroendocrine-to-endocrine pathway? (tf kinda name) (9)

A
  1. Stimulus -> Sensory Cell
  2. Sensory Cell -> Neurotransmitters
  3. Neurotransmitters -> CNS
  4. CNS -> Neurohormone
  5. Neurohormone -> Endocrine Cell
  6. Endocrine Cell -> Hormone
  7. Hormone -> Effector Cell
  8. Effector Cell -> Response
  9. Feedback Inhibition -> CNS + Sensory Cell
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12
Q

What is Feedback Inhibition?
What is Positive feedback?

A

In Feedback Inhibition, the product of a process inhibits its function.

In Contrast, Positive Feedback occurs when the product of the process stimulates (Increases) its production.

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13
Q

What are the 3 kinds of Hormones?

Where can u find them in the cell?

A
  1. Peptides and Polypeptides (Secretin) on Membrane Receptors
  2. Amino Acid Derivatives (Adrenaline) on Membrane Receptors
  3. Steroids (Cortisol) on Intracellular Receptors

Note There are also Thyroid Hormones which are Fatty Acid Derivatives but fuc em

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14
Q

What are two fundamental pathways for Hormones?

A
  1. Water-soluble (hydrophilic) hormones
    (Peptides and amino acid derivatives)
  2. Water-insoluble (lipophilic) hormones
    (steroids)
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15
Q

Examples of Steroid Hormones?

A
  • cortisol: stress response
  • anabolic steroids - muscle growth
  • sex steroids: estrogens, testosterone
  • aldosterone ; Na+ resorption in kidney
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16
Q

Why do we need Thyroid Hormones

A

Thyroid Hormones are composed of Iodine, which is why the salt we buy is often fortified with iodine.

A Lack of Thyroid Hormones causes us to feel tired, sluggish and unproductive (like BISC 101)

During the Cold War, people would stock up on iodine tablets in order to prevent the accumulation of radioactive iodine that could destroy our thyroid gland

17
Q

What actions do Steroid Hormones take during Gene Expression?
(Up-Regulation)

A
  1. Hormone Diffuses into Target Cell through Membrane
  2. Hormone Binds to Receptors in the Cytosol and moves into the nucleus
  3. Hormone Receptor Complex enters the nucleus and binds to DNA (hormone response element), inducing the start of transcription
  4. Gene Expression is turned on
    Many mRNA Transcripts are produced amplifying the signal
  5. In the cytosol, proteins are translated
18
Q

What’s the difference between Up-Regulation and Down-Regulation?

A

Up-Regulation turns on the Gene Expression

Down-Regulations Turn off the Gene Expression

(Only in cells with the right Hormone Receptor)

19
Q

What must Target Cells have to “accept” a steroid hormone?

A

They must have the right Intracellular Receptor.

20
Q

What are Homo-Dimers?
What are Hetero-Dimers?

A

Homo-Dimers - two identical proteins/hormones

Hetero-Dimers - two different proteins/hormones

21
Q

Describe in detail the mechanism by which steroid hormones induce a specific response in their target tissues.

A

Steroid hormones are water-insoluble, and hence normally need a transport protein to reach their target tissues. Because of their lipophilic nature, they can easily diffuse through the cell membrane but need an intracellular receptor that moves the hormone through the cytosol and into the nucleus.

Steroid hormones normally act by modifying gene expression; the hormone-receptor complex binds to control regions on the DNA for these genes, called hormone response elements. As long as the hormone receptor complex remains bound to its response element, the rate of transcription for the gene is turned up (upregulation) or, seldom, down (downregulation). When the hormone is broken down or otherwise removed from its receptor, the activation of the gene stops.

22
Q

What hormones are present during Insect Metamorphosis?

A

ecdysone - triggers each molting

juvenile hormone - causes larva-larva molting

23
Q

What are some Hydrophilic Hormones?

A
  • growth hormone (GH): organ and muscle growth
  • growth hormone release hormone
  • antidiuretic hormone (reabsorption of water)
  • insulin, glucagon (control blood sugar)
  • leptin (regulation of lipid storage)
  • adipokinetic hormone (insects, fat mobilization)
24
Q

What does Adrenaline do?

A

Adrenaline “Fight or flight” hormone
* dilates pupils (vision) up
* pain sensitivity (down)
* heart rate (up)
* metabolic rate (up)
* oxygen (up)
- glucose (up)

25
Q

What does Adrenaline activate? Why?

A

When we are in danger we need more glucose because we need more energy, however, we don’t have time to eat, so we rely on an enzyme.

Phosphorylase which is present in the liver (high glucose levels) catalyzes the reaction that breaks down glycogen into glucose. It is activated by a phosphate.

Phosphorylase is usually present in its inactive form but the protein KINASE catalyzes the reaction that brings over a phosphate from an ATP molecule

Therefore, Adrenaline works to activate KINASE by binding to a membrane receptor.

Known as Phosphorylase Kinase.

26
Q

How does a signal from adrenaline trigger increase glucose levels? (8)

A
  1. The Adrenaline Binds to a Membrane Receptor.
  2. The Receptor Activates a “G Protein” that is connected to it
  3. The G Protein activates the enzyme Adenylyl Cyclase
  4. The Adenylyl Cyclase catalyzes the formation of Cyclic AMP, or cAMP
  5. cAMP activates Kinase A
  6. Kinase A activates Phosphorylase Kinase by bringing over phosphorus from ATP
  7. Phosphoylase is activated
  8. Glucose is cleaved from Glycogen.
27
Q

True or False
Hormones act directly on almost all cells in the body

A

FALSE
hormones only affect target cells with specific receptors which recognize and bind with particular hormones

28
Q

True or False
A hormone’s interaction with its target cells depends on its lipid solubility

A

TRUE

29
Q

True or False
Protein hormones bind to receptors on the cell’s nucleus

A

FALSE
protein hormones bind to receptors on the cell membrane, only steroid/thyroid hormones bind to receptors on the nuclear membrane (or in the cytosol)

30
Q

True or False
Digestion is regulated primarily by the hypothalamus and pituitary.

A

FALSE
digestion is one of the few processes that function almost autonomously in the body

31
Q

True or False
The endocrine system does not play a major role in arthropods

A

FALSE
controls metamorphosis in insect development

32
Q

What transports hormones in animals?

A

Blood/hemolymph

33
Q

What are the neuro-endocrine systems long term and short-term responses to stress?

A

Short-term- release of epinephrine and norepinephrine
Long term- release of cortisol

34
Q

Explain how lipid solubility affects storage, transport, and mode of cellular action in protein versus steroid hormones.

A

Protein hormones
-can be stored in membrane-bound vesicles
-are soluble in blood and can be transported freely through the bloodstream and bind to signal receptors on the cell membrane (cannot pass through into cell without receptor)
-changes cell function via signal transduction within the cell (cytosolic or genomic effects)
Steroid hormones (thyroid hormones work the same way)
-cannot be stored in vesicles so produced as they are needed
-must be transported through the blood with the help of a transport protein
-pass straight through into the cell (no receptor on the cell membrane)
-bind to receptors within the cell to produce a transcription factor that changes cell function via gene expression (NOT cytosolic effects)

35
Q

Water Soluble Membranes typically what?

A

water-soluble hormones bind to the membrane receptor

activated receptor initiates second messenger production via G-protein

signalling cascade needs to cellular response