Hormones And Cell Signalling

Front 1

cell signaling is______. The signaling cell_______. The target cell_________.

Back 1

communication between cells, sends the signal, receives the signal

Front 2

Types of cell signaling:

Back 2

Direct and Indirect

Front 3

Direct signaling

Back 3

-through Gap Junctions
-hydrophillic chemical messengers can travel directly through lipid membrane
-typically involves movement of ions

Front 4

Indirect signalling

Back 4

signaling cell releases a chemical messenger that binds to a receptor on the target cell and activates a signal transduction pathway.

Front 5

paracrine signaling

Back 5

-over short distance
-diffusion to nearby cell

Front 6

autocrine signaling

Back 6

-over short distance
-diffusion back to the signaling cell

Front 7

endocrine signaling

Back 7

-over long distances
-hormone is transported by the circulatory system

Front 8

Neural signaling

Back 8

electrical signal travels along a neuron and releases a neurotransmitter

Front 9

Two main types of cell messengers

Back 9

1. hydrophilic
2. hydrophobic

Front 10

Gap junctions

Back 10

-specialized protein complexes that create an aqueous pore between two adjacent cells

Front 11

Indirect signaling
3 Steps:

Back 11

1. release of chemical messengers from the signaling cell
2. transport of the messenger through the extracellular environment to the traget cell
3. communication of the signal to the target cell

Front 12

release of chemical messengers
Hydrophobic and hydrophilic

Back 12

-hydrophobic messengers: can cross the cell membrane by diffusion
-Hydrophilic messengers: packed into vesicles where they are stored until released by exocytosis

Front 13

exocytosis

Back 13

vesicles fuse with the plasma membrane and release contents

Front 14

Transport of hydrophilic messengers to the target cell

Back 14

the messengers dissolve in aqueous solutions like extracellular fluid and blood.

Front 15

transport of hydrophobic messengers to the target cells.

Back 15

-hydrophobic messengers bind to carrier proteins in the blood
-some do not bind to carrier proteins
-circ system carries the free and bound messenger towards target cell
-free messenger enters target cell and binds to receptor, bound messenger cannot enter the target cell
-the decreasing concentration of free messenger causes bound messenger to dissociate from the carrier protein, allowing it to enter target cell.

Front 16

carrier protein

Back 16

help hydrophobic messengers dissolve in aqueous solutions

Front 17

receptors for hydrophobic messengers

Back 17

are intracellular protiens

Front 18

receptors for hydrophilic messengers

Back 18

are transmembrane protiens

Front 19

Ligand, What it is and what it does

Back 19

chemical messenger that can bind to a specific receptor. The receptor changed shape when it binds to the receptor. Only corrected shaped ligand can bind to a receptor.

Front 20

ligand mimics, what they are and what they do

Back 20

Antagonist- block the receptor but produce no signal (decreases over all signal by decreasing available binding sites fro natural ligand)

Agonist- activates the receptor and produces a signal (signal can be produced when no natural ligand is present or signal is enhanced if natural ligand is present too)

Front 21

More free ligand will ______response. More receptors will ______ response. Receptors can become_________.
Increasing affinity constant (Ka) will______ response

Back 21

increase, increase, saturated, increase

Front 22

Down Regulation

Back 22

constant exposure to the ligand will lead to a decrease in the number of receptors (receptor desensitization)

Front 23

Up-regulation

Back 23

constant exposure to ligand will lead to a increase in the number of receptors.

Front 24

Signal transduction pathways

Back 24

concert the change in shape of the ligand-receptor complex into a complex intracellular response.

Front 25

Transducers

Back 25

-convert signals from one form to another

Front 26

4 components of the signal transduction

ran to a rat

Back 26

1. Receiver: ligand binding receptor
2.Transducer: conformational change of receptor
3. Amplifier: signal transduction pathway increases the number of molecules affected
4. Responder: something that responds to the signal

Front 27

Types of receptors

Back 27

-Ligand gated ion channels
-Receptor enzymes
-G-protein coupled receptors
-Intracellular receptors

Front 28

Intracellular receptors

Back 28

can regulate the transcription of target genes by binding to the specific DNA sequences and increasing or decreasing mRNA production.
-The ligand-receptor complex translocates to the nucleus and DNA binding domain of the receptor binds to a specific DNA sequence and the transactivating domain interacts with TXN factors bound in the same region.

Front 29

Ligand gated ion channels

Back 29

-ligand binds to the receptor
-receptor changes shape, opening the channel
-ions move across the membrane
-concentration and electrical gradients dictate the direction of ion movement
-movement of ions changes ion concentration which alters membrane potential

Front 30

Receptor Enzymes

Back 30

-when activated the catalytic domain starts a phosphorylation cascade
-names based on the reaction catalyzed
ex tyrosine kinase, serine/threonine kinase, guanylate cyclase

Front 31

G-protein coupled receptors

Back 31

-transmembrane protein interacts with intracellular g-protein.
-activate second messengers
-have ability to bind guanosine nucleotides ( alpha subunits swap gdp for gtp when active, the active alpha subunit then dissociates and moves through membrane to interact with amplifier enzyme which then activates a second messenger)

Front 32

second messenger Ca2+
1. synthesized by the enzyme:
2. action:
3. effect:

Back 32

1. none
2. binds to calmodulin
3. alters enzyme activity

Front 33

second messenger cGMP
1. synthesized by the enzyme:
2. action:
3. effect:

Back 33

1. guanylate cyclase
2. activates protein kinases (usually PKG)
3.phosporylates proteins, open and closes ion channels

Front 34

second messenger cAMP
1. synthesized by the enzyme:
2. action:
3. effect:

Back 34

1. adenylate cyclase
2. activates protein kinases usually PKA
3.phosphorylates proteins

Front 35

second messenger Phosphatidylinositol
1. synthesized by the enzyme:
2. action:
3. effect:

Back 35

1.Phospholipase C
2.Activates protein kinase C, stimulates Ca2+ release from intracellular stores.
3. alters enzyme activity phosphorylates proteins

Front 36

secretory cell of:
1. autocrine/paracrine
2.nervous
3. endocrine

Back 36

1. various
2. neuron
3. endocrine

Front 37

target cell of:
1. autocrine/paracrine
2.nervous
3. endocrine

Back 37

1. most cells in body
2. neuron, muscle, endocrine
3. most cells in body

Front 38

maximum signaling distance
1. autocrine/paracrine
2.nervous
3. endocrine

Back 38

1.short
2. long
3 long

Front 39

signal type
1. autocrine/paracrine
2.nervous
3. endocrine

Back 39

1. chemical
2. chemical and electrical
3. chemical

Front 40

Transport
1. autocrine/paracrine
2.nervous
3. endocrine

Back 40

1. extracellular fluid
2. synapses
3. circ system

Front 41

speed
1. autocrine/paracrine
2.nervous
3. endocrine

Back 41

1. rapid
2. rapid
3. slower

Front 42

duration of response
1. autocrine/paracrine
2.nervous
3. endocrine

Back 42

1. short
2. short
3. longer

Front 43

Eicosanoids

Back 43

act only in paracrine and autocrine signalling

Front 44

prostaglandins

Back 44

involved in pain reception; blocked by many painkillers

Front 45

nervous system

Back 45

-collection of cells that can carry signals across long distances
-neurons allow electrical signals to be propagated across long distances within a cell

Front 46

synapse

Back 46

region between two neurons or a neuron and other target cells
-gap junctions
-neurotransmitters

Front 47

endocrine system

Back 47

- sends chemicals (hormones) through the blood
-produced by endocrine glands
-other chemicals can act as hormones ex neurohormones
-nonendocrine organs like the heart can produce hormones

Front 48

3 types of hormones

Back 48

-steroid
-peptide
-amines

Front 49

peptide hormones

Back 49

-are hydrophilic
-made in advance
-stored in secretory vesicles
-released by exocytosis
-transported dissolved in plasma
-have a short half life
-receptors are located on cell surfaces
-they activate second messenger pathways

Front 50

Steriod hormones

Back 50

-are hydrophobic
-synthesized on demand
-not stored
-are released by diffusion
-transported by carrier protiens
-have a long half life
-have receptors in cytoplasm or in nucleus (some on cell surface)
-alter gene expression but some non genomic responsibilities as well

Front 51

amines:
catecholamines

Back 51

-hydrophilic
-made in advance
-stored in secretory vesicles
-released by exocytosis
-transport dissolved in plasma
-short half life
-receptors on cell surface
-activates second messengers

Front 52

amines:
thyroid hormones

Back 52

-hydrophobic
-made in advance
-precurser is stored in secretory vesicles
-released by diffusion
-transported bound to carrier protiens
-have long half life
-receptors are located in the nucleus
-alter gene expression

Front 53

pepide hormones are sythesized in the

Back 53

rough ER

Front 54

steps in peptide hormone synthesis

Back 54

1. translated in rough er
2.preprohormone is in lumen, cleaved of signaling sequence and enters vesicle as prohormone
3.goes to golgi
4.in the secondary vesicle a peptide fragement is cleaved and active hormone present

Front 55

synthesis of steriod hormones

Back 55

1. derived from cholesterol
2.enzymes for synthesis are in smooth ER and mitochondria
3. cannot be stored in cell so must be produced on demand
-sloow effects except for the stress hormone cortisol which has rapid non genomic effects

Front 56

three classes of steroid hormones

Back 56

1. mineralocorticolids-electrolyte balance ex. aldosterone
2. glucocorticoids-stress hormones ex. cortisol
3. reproductive hormones-regulate sex specific characteristics and reproduction

Front 57

amine hormones

Back 57

-possess amine (-NH2)
-some true hormones
-some neurotransmitters
-some both (acetylcholine, serotonin, melatonin, histamines)
- have diverse effects

Front 58

exocrine cell signaling

Back 58

-secretions via ducts to the outside of the body including skin, respiratory surfaces and the gut
-cell to cell, pheromones, allelochemicals

Front 59

Positive feedback

Back 59

output acts as further stimulus
-outside factor is required to shut off the positive feedback cycle

Front 60

negative feedback

Back 60

output reduces the stimulus

can be direct, first, second or third order ect.

Front 61

direct feedback

Back 61

-simplest system
-endocrine gland acts as the receptor, intergrating center and the endocrine gland.
-stimulate endocrine gland which then sends hormone to target cell

example: parathyroid hormone

Front 62

first order feedback

Back 62

-stimulate sense organ
-signal is intergrated and then stimulates target cell

Front 63

2nd order feedback

Back 63

-stimulate sense organ
-signal is intergrated and then stimulates endocrine gland
-hormone is then sent to target cell

Front 64

3rd order feedback

Back 64

-stimulate sense organ
-signal is intergrated and then stimulates endocrine gland
-hormone is then sent to second endocrine gland that is then stimulated
-2nd hormone stimulates target cell

Front 65

parathyroid hormone

Back 65

stimulus: low plasma Ca2+
endocrine gland: parathyroid gland
target organ: kidneys and bones
Respones:kidneys retain calcium and bones release it. so plasma concentration of Ca+ increases and is negative feedback

Front 66

epinephrine 2nd order feedback

Back 66

-flight or fright response
-sense organs preceives an alarming stimulus
-sensory nerves send signal to the brain
-brain intergrates the signal and sends signal out via motor nerves
-adrenal medulla responds to signal by releasing epinephrine
-epinephrine interacts with heart and muscles

Front 67

Insulin

Back 67

-direct stimulus response and second order feedback
-cck-stimulates digestion
-ach-major NT used during digestion
-stretch receptors in digestive tract and glucose receptors and inc in blood glucose cause pancreas to secrete insulin

Front 68

posterior pituitary

Back 68

-extension of hypothalamus
-neurons originate in hypothalamus and terminate in the posterior pituitary
-cell bodies synthesize neurohormones that travel in vesicles down axons
-eg oxytocin and vasopressin
-first order endocrine pathway

Front 69

anterior pituitary

Back 69

-hypothalamus synthesizes and secretes neurohormones
-portal system to anterior pituitary
-tropic hormones cause release of another hormone
-3rd order endocrine pathway

Front 70

tropic hormones

Back 70

cause release of another home
ex. TSH stimulates the thyroid gland to release thyroid hormones

Front 71

regulation of blood glucose is tightly controlled. To low__________To high___________. Hormones used____________. The hormones have ___________ pairing which means they__________________. Beta cells of pancreas release______ and alpha release__________.

Back 71

brain cannot function, osmotic balance of blood is disturbed, insulin and glycogen, anatgonistic pairing, have opposite effects, insulin, glycogen

Front 72

similarities between plants and animals pathways

Back 72

-use calcium as secondary messenger
-have pathways that involve protien kinases

Front 73

differences between plants and animals pathways

Back 73

-plants do not have receptor tyrosine kinases or RAS protiens
-plants have unique transmembrane serine and threonine kinases

Front 74

vertebrates vs invertebrates

Back 74

-all have nervous systems except sponges
-circ and endocrine systems developed independently in several groups
-all vert use a series of steroid hormones and invert just use esterogen
--insects/crustaceans use different series of steroids to regulate molting and metamorphosis

Front 75

vertebrates horomones have alterations in the ______ tissues respond to a hormone rather then a change in the _____________

Back 75

-way, hormone

Front 76

prolactin

Back 76

-stimulates milk production in mammals and inhibits metamorphosis and promotes growth in amphibians and regulates water balance in fish.

Front 77

adrenal glands

Back 77

-on kidneys
-have interrenal and chromaffin tissue