hormonii 1 Flashcards

1
Q

what are hormones important for

A

to understand basic biological functions of the brain and the body
we can better understand psychological states and behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the endocrine system

A

a chemical communication system of the body

includes glands and hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are glands

A

structures which secrete or produce specific chemical substances

glands are the target for signals that tend to come from the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are hormones

A

chemical messengers released in response to these signals

hormones are the ways in which certain parts of the body communicate

hormones are released through the blood stream

glands release hormones in the capillary and hormones travel towards a target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the functions of the endocrine system

A
  1. maintenance of the internal environment in the body - homeostasis
  2. regulation of growth and development
  3. control, maintenance and instigation of sexual reproduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the neuroendocrine system

A

hypothalamus and pituitary gland - located in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is hormonal signalling

A

a complex way to refer to the way hormones are produced and target the destination cells or glands

  1. There is a change in the body or environment which is picked up by hypothalamus - master mind of the endocrine system
  2. Hypothalamus works in close collaboration with the pituitary gland by releasing a set of hormones that induce or trigger a number of responses in the pituitary gland
  3. Pituitary gland triggers additional hormones and those hormones either target a tissue or another gland and 4. those would exert a particular action
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the hypothalamus

A

deep inside the brain
made up of a number of subparts which take the name of nuclei

nuclei are critical for different functions in the hypothalamus

nuclei allow the hypothalamus to be specialised in a variety of functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the hypothalamus aim

A

to maintain homeostasis - internal balance

our body needs to have certain balance in order to operate optimally

hypothalamus operates to promote the releasing or stop the releasing of hormones so that certain basic functions like temperature are maintained at optimal level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the pituitary gland

A

small structure
controls a number of other glands and organs

connected to the hypothalamus to form the neuroendocrine system

divided into anterior and posterior lobe

hard to reach in case of injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the properties of hormones

A

hormones are produced and released in secreting cells

hormones have an effect at a site different from where they are made - target cells

hormones travel through the bloodstream

they fit precisely onto a target cell’s receptors so they are specific for a particular cell

= specific hormones for specific receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the classification of hormones

A
  1. chemical criteria
    - steroid hormones
    - peptide hormones
  2. functional criteria
    GENERAL
    - activating effects
    - organisational effects

SPECIFIC
- homeostatic hormones
- glucocorticoids hormones
- gonadal (sex) hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are steroid hormones (chemical classification)

A

steroid hormones are hormones that are fat soluble - they can cross the cell membrane

this means hormones are capable on acting on the target cells DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the journey of the steroid hormones

A

they cross the cell membrane

in cytoplasm they find steroid receptor

hormone will bind onto steroid receptor

then enters nucleus of the cell

here it will bind to mRNA and act on the cell DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are peptide hormones

A

hormones which are not fat soluble so can’t cross the cell membrane

peptide hormones bind on a receptor on brown structures which sit on the cell membrane and it will not be able to enter cell

so they do not act directly on cell’s DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the 2 GENERAL functions of hormones

A

Activating effect or
Organisational effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are activating effects

A

activating effect is a reversible change in terms of the properties of the cell

it happens when the hormone is sitting on the receptor of a cell

the effect would last for a short amount of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are organisational effects

A

permanent or semi-permanent change in the structure of the nervous system

happens during a particular point in life - sensitive period in early development

hormones aka steroid hormones enter the cell’s nucleus and affect gene expression

steroid hormone can reach all the way into the nucleus and bind onto the mRNA and act on DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the 3 types of SPECIFIC functions

A
  1. Homeostatic hormones
  2. Glucocorticoids hormones
  3. Gonadal (sex) hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are homeostatic hormones

A

hormones that aim to maintain a metabolic balance - homeostasis

and they regulate a number of physiological systems

homeostatic hormones exert an activating effect so action is only temporary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is keeping the balance important

A

certain critical parameters need to be at a constant level so that the rest of the organs can function normally

e.g.
if we are asleep we are not able to control temperature so those functions need to look after themselves

there are a no. of physiological conditions that need to be maintained in a balanced way so we can operate normally

any imbalance will have devastating effect on the organs

22
Q

what is an example of homeostatic hormones

A

insulin

makes sure glucose is maintained at optimal level
produced by pancreas
- the action of insulin promotes glucose intake by being released in the bloodstream and unblocking cells so they can take up glucose

23
Q

why is the action of insulin important

A

cells use glucose for their energy requirements and cells can obtain glucose from blood

24
Q

who uses insulin

A

muscles cells use glucose but they can also use other substances for fuel like protein and fat

HOWEVER
neurones can only use glucose

if glucose is low, priority is given to neurones
neurones cannot store glucose so they depend on the availability of glucose in the bloodstream

HENCE
we need to have a system in place that is able to maintain glucose at an optimal level

25
how does insulin work
when insulin is in proximity with cell, insulin receptors bind with insulin molecule glucose channel opens up and glucose enters cells and is used as energy supply SO insulin enters bloodstream from pancreas insulin binds to receptor insulin on receptor opens glucose channel glucose leaves bloodstream and enters cell through glucose channel
26
what is the step by step process of insulin
Physiological changes happen. These changes are picked up by the hypothalamus. Change is translated into a message that is sent to medulla in brainstem. Message will travel towards pancreas via the vagus nerve. That induces pancreas to secrete insulin.
26
how are levels of glucose in the blood detected
there are chemoreceptors that can detect how much glucose is in the blood
27
what happens if there is too much glucose in the blood
Triggers the released of insulin Cells take up the glucose
28
what happens if there is too little glucose
secretion of insulin is stopped and cells are unable to pick up glucose There has to be residual glucose available in case neurones need it
29
what happens if there is fall in blood sugar levels
Hypoglycaemia can cause fainting or coma Neurones do not function properly as they depend on glucose Symptoms resolve when the sugar level returns to normal
30
what happens when there is rise in blood sugar levels
Hyperglycaemia deficiency in production of insulin or defective insulin receptors type 1 and 2 diabetes you have sugar but cells are not capable of using it
31
what is type 1 diabetes
little or no insulin produced we have glucose in the stomach and enters the blood stream pancreas should make insulin so glucose can be used by cells instead there is little insulin made and sugar remains available in the blood stream and is not used up
32
what is type 2 diabetes
insulin receptors become defective. body produces insulin but insulin molecules are not able to bind to receptors so less glucose is used by cells
33
what are glucocorticoids hormones
control stress and regulate metabolism exert an activating effect so action is only temporary
34
what is stress
the body's reaction to feeling threatened or under pressure. stress is stimulus that challenges homeostasis of the body and triggers arousal in humans
35
what is the physiological response of stress
response to stress is the same irrespective of the stressor - exciting or frightening
36
how do we activate a stress response
when we face a stressful situation we mobilise our body resources so we can respond to stress and achieve a point where we rebalance the situation and restore homeostasis
37
what is fast acting system based on
Nervous system: sympathetic pathway Hormonal system: adrenaline and noradrenaline
37
what is the slow acting system based on
Hormonal response: HPA (Hypothalamus pituitary gland adrenal cortex) axis - from adrenal cortex
37
how are fast actions implemented by the endocrine system - adrenal gland
adrenal gland - made of cortex and medulla
37
how can we activate a stress response using 2 systems
Fast acting Slow acting
37
what is the fast acting system
when we make a split second decision about if something dangerous requires escaping it or facing it we need certain level of energy resources which result from cell metabolism being stimulated to prepare for action increase heart rate decrease in digestive system immune system is stimulated to use if we get injured
37
what are glucocorticoids
glucocorticoids hormones break down protein and fat metabolism
38
what is the slow acting stress response based on
the action of the endocrine system hypothalamus sends trigger to anterior pituitary gland which sends a message to adrenal cortex which produces 2 types of hormones - glucocorticoids hormones and mineralocorticoids hormones
38
how is adrenaline triggered using the fast acting system
the trigger to produce adrenaline is coming from the hypothalamus which picks up a certain level of stress stimulus and sends the trigger to produce adrenaline vis spinal cord to adrenal medulla
38
what is the adrenal medulla
part of the autonomic nervous system capable of secreting hormone adrenaline which activates sympathetic responses - increase in heart beat
39
what are mineralocorticoids
hormones that act on blood volume and pressure which tends to increase and they act on the balance of water which is reabsorbed by kidneys
40
what is the slow acting response as used by the HPA axis
HPA axis: from hypothalamus to pituitary gland to adrenal cortex glucocorticoids hormones like cortisol are produced
41
what is the action of glucocorticoids hormones
cortisol is a typical glucocorticoid hormone glucocorticoids make sure glucose is released from fat and proteins by the liver all systems that are not required to deal with stressor are turned off - reproductive functions are off
42
what happens if stress response is not shut down
if stress does not result in restoring homeostasis, results in chronic stress continued production of glucocorticoids has a neurotoxic effect on the brain
43
what are the physical consequences of stress
Proteins are used up which results in muscle wasting and fatigue Growth hormone is inhibited Reproductive functions are inhibited
44
what are the cognitive consequences of stress
memory and learning hippocampus deals with memory the hippocampus contains high density of cortisol receptors - able to detect amount of cortisol in blood constant high level of cortisol damages the hippocampus hippocampus informs the hypothalamus when cortisol is too high and induces hypothalamus to induce pituitary gland to reduce amount of cortisol too much cortisol can become toxic and neurones in hippocampus are unable to respond then they are less able to inform hypothalamus that there is too much cortisol produced