Hormonal Communication paper 1

what is the role of the endocrine system

it uses hormones to send information about changes in the environment around the body to bring about a response

what are hormones

chemical messengers that bind to specific receptors on target cells. This stimulates the target cell to produce a response

how do hormones act as chemical messengers

1. hormones are produced by endocrine gland cells

2. when stimulated, glands release hormones into the blood stream

3. the blood carries hormones to their target cells

4. they attach to receptors on or inside target cells

5. the cells then respond to the hormones

what are the two classes of hormones

non-steroid (peptide) and steroid

what is the difference in solubility between peptide and steroid hormones

peptide are water soluble (hydrophilic) and steroid are lipid soluble (hydrophobic)

can non-steroid hormones diffuse across the phospholipid bilayer

no because they are hydrophilic and polar

can steroid hormones diffuse across the phospholipid bilayer

yes because they are non-polar and hydrophobic

what is the mechanism of action for non-steroid (peptide) hormones

bind to receptors on the cell-surface membrane of their target cells to activate second messengers.

what is the mechanism of action for steroid hormones

bind to receptor molecules in the cytoplasm or nucleus, forming a hormone-receptor complex that acts as a transcription factor.

formed from steroid hormones, what does a hormone-receptor complex do

it acts as a transcription factor

give examples of a non-steroid (peptide) hormone

adrenaline, glucagon, insulin

give examples of steroid hormones

oestrogen, testosterone, progesterone, glucocorticoids

compare the endocrine and nervous system

Feature	Endocrine system	Nervous system
Signals	Hormones	Nerve impulses
Transmission	By blood	By neurones
Speed	Slow	Very rapid
Spread	Widespread	Localised
Duration of effect	Long	Short

describe the shape and structure of the adrenal glands

a pair of small, triangular endocrine glands located above each kidney.

name the two main regions of the adrenal glands

1. adrenal cortex

2. adrenal medulla

describe the adrenal cortex

the outer region of the adrenal glands, responsible for producing vital steroid hormones

describe the adrenal medulla

the inner region at the centre of the adrenal glands, known for producing catecholamine hormones

give three examples of hormones synthesised and released from the adrenal cortex

1. glucocorticoids

2. mineralocorticoids

3. androgens

what are the functions of glucocorticoids

1. regulate metabolism by controlling the conversion of fats, proteins and carbohydrates to energy.

2. control blood pressure and stress responses

3. regulate the immune response and suppress inflammation

what is the function of mineralocorticoids

1. maintain blood pressure by balancing salt and water in the blood and body fluids

what is the function of androgens

1. regulation of sexual characteristics and cell growth

give examples of glucocorticoids

1. cortisol

2. corticosterone

give an example of a mineralocorticoid

aldosterone

give an example of an androgen

testosterone

where do the chemical signals come from to ensure the release of hormones from the adrenal glands

hypothalamus and kidneys

what are catecholamines

hormones that prepare the body for stressful or dangerous situations

when are catecholamines released

when the sympathetic nervous system is stimulated

what are the two main catecholamine hormones

1. adrenaline

2. noradrenaline

   they work together to help the body respond to stress and activate the body’s fight or flight mechanism

list the effects of adrenaline

1. increases heart rate and blood pressure to increase blood flow to the muscles and brain

2. increases blood glucose levels

3. increases breathing rate

4. dilates bronchioles

list the effects of noradrenaline

1. increases heart rate

2. expands air passages

3. dilates pupils

4. narrows blood vessels in organs like the gut to reduce blood flow to regions that aren’t helpful in the stress response.

what is the exocrine glandular tissue made up of in the pancreas

pancreatic acini

what does the pancreatic acini contain

acinar cells that produce digestive enzymes like amylases, proteases and lipases, aswell as alkaline pancreatic juice

where do acinar cells travel in the pancreas

through the pancreatic duct and are released into the duodenum

what is the duodenum in the pancreas

the initial segment of the small intestine, where pancreatic acini assist with digestion

what cells do Islets contain

Beta cells and Alpha cells

what hormone do Beta cells secrete

insulin

what hormone do Alpha cells secrete

glucagon

what can extreme blood glucose levels lead to

osmotic imbalances in cells, potentially causing cell death

what type of feedback mechanism is used to control blood glucose levels

negative feedback

what happens once beta cells have secreted insulin

1. decreased glucagon secretion

2. more glucose taken up by cells

3. increased respiration

4. glycogenesis

   blood glucose levels decrease

what happens once alpha cells have secreted glucagon

1. decreased insulin secretion

2. less glucose taken up by cells

3. decreased respiration

4. glycogenolysis

5. gluconeogenesis

   blood glucose levels increase

how is glucose uptake increased in cells

insulin increases the permeability of muscle and fat cells to glucose

what is glycogenesis

glucose is converted into glycogen for storage, primarily in the liver

glycogenolysis

glycogen is converted back into glucose in the liver and muscle cells

what is gluconeogenesis

glucose is produced from amino acids and fats in the liver

how does adrenaline work with glucagon to increase blood glucose levels

when levels are too low, adrenaline promotes glycogenolysis and gluconeogenesis in liver and muscle cells

describe the process of ‘stimulus-secretion coupling’ of insulin secretion from Beta cells

1. glucose enters Beta cells via transport proteins

2. increased cellular respiration produces more ATP in mitochondria

3. ATP prompts the closure of potassium ion channels

4. this causes an increase in potassium ion concentration inside the cell

5. the rise in potassium levels leads to depolarisation, opening calcium ion channels

6. the calcium ion influx stimulates insulin release through exocytosis

what is Diabetes Mellitus

a condition characterised by improperly regulated blood glucose levels

give a sign of diabetes

glucose in urine, because it indicated that the kidneys are unable to reabsorb all glucose from the filtrate into the blood

what is a biosensor

something that people with diabetes use to monitor blood glucose concentration using a small blood sample.

what type of diabetes results from an autoimmune disease destroying insulin-producing beta cells in the pancreas

type 1

what type of diabetes occurs when beta cells don’t produce enough insulin or when the body’s cells resist insulin

type 2

what type of diabetes results in higher than normal blood glucose levels

type 2

what type of diabetes leads to no insulin production and high blood glucose levels

type 1

what type of diabetes typically develops in childhood or early adulthood

type 1

what type of diabetes commonly develops later in life and is related to obesity

type 2

give features of type 1 diabetes

1. Often results from an autoimmune disease destroying insulin-producing beta cells in the pancreas.

2. Leads to no insulin production and high blood glucose levels.

3. Typically develops in childhood or early adulthood.

give features of type 2 diabetes

1. Occurs when beta cells don't produce enough insulin or the body's cells resist insulin.

2. Results in higher than normal blood glucose levels.

3. Commonly develops later in life and is associated with obesity.

what type of therapy is essential for regulating glucose levels in type 1 diabetes

insulin therapy

list treatments of type 1 diabetes

• regular insulin injections for most individuals

• use of an insulin pump providing continuous insulin administration

• Pancreas transplants of healthy Islet cells to enable some insulin production

• careful blood glucose monitoring and a diet balanced with insulin dosage

• exercise to help regulate blood glucose and insulin requirements

what is the initial approach in managing type 2 diabetes. If this fails, what is the next approach

1. lifestyle changes such as diet, exercise and weight loss

2. medications

list treatments for type 2 diabetes

• diet control to reduce sugar intake

• regular physical activity

• medications to increase cells’ sensitivity to insulin

• medications to stimulate more insulin production in cells

• in some cases, insulin therapy is necessary

how could stem cells cure diabetes

• growing stem cells into Beta cells

• implanting these Beta cells into the pancreas of individuals with type 1 diabetes

• this allows them to produce their own insulin

list the benefits of using genetically modified bacteria to produce insulin

• reduced production costs

• capability to produce insulin in large quantities

• enhanced effectiveness

• lower risk of allergic reactions

• avoids ethical and religious concerns associated with animal-derived products

what is the name of an instinctive reaction to perceive threats

fight or flight response

what does the fight of flight response do

it prepares the body to either flee or confront danger

what is the mechanism for the fight or flight response

1. the autonomic nervous system detects a threat, and the signal is passed on to the hypothalamus

2. the hypothalamus activates the sympathetic nervous system, sending nerve signals to glands and muscles.

3. the sympathetic nervous system triggers the secretion of adrenaline and noradrenaline from the adrenal medulla, causing various physiological changes

4. the hypothalamus also communicates with the adrenal-cortical system, stimulating the pituitary gland to release adrenocorticotropic hormone (ACTH)

5. ACTH travels via the bloodstream to the adrenal cortex, stimulating it to release several other hormones to help the body deal with the threat.

what detects and threat during the fight or flight response

the autonomic nervous system

where does the signal go after the autonomic nervous system

ia signal is passed onto the hypothalamus

what is activated by the hypothalamus

the sympathetic nervous system

what does the sympathetic nervous system trigger

the secretion of adrenaline and noradrenaline

where are adrenaline and noradrenaline secreted from

the adrenal medulla

what does the secretion of adrenaline and noradrenaline from the adrenal medulla cause

physiological changes

what other system does the hypothalamus communicate with

the adrenal-cortical system

what does the adrenal-cortical system stimulate

stimulates the pituitary gland to release adrenocorticotropic hormone (ACTH)

what does ACTH do

it travels in the bloodstream to the adrenal cortex, which stimulates it to release several other hormones to help the body deal with the threat.

list some physiological reactions triggered in the fight or flight response

• increased heart rate

• pupil dilation

• constriction of arterioles in skin

• rise in blood glucose levels

• relaxation of airway muscles

• digestion stops

what is the purpose of increasing heart rate

to circulate more oxygenated blood around the body

what is the purpose of pupil dilation

to improve vision

what is the purpose of constriction of arterioles in skin

to divert more blood to major muscles, brain, and heart.

what is the purpose of a rise in blood glucose levels

to increase cellular respiration

what is the purpose of relaxation of airway muscles

to allow more oxygen into the lungs

what is the purpose of digestion stops

to prioritise emergency bodily functions

simply, what is the second messenger model

it involves a hormone (the first messenger) triggering the formation of a second messenger (cAMP) inside the cell, which activates enzymes to carry out a function

what is an example of a second messenger model in cell signalling

adrenaline during the fight or flight response

what hormone plays a role in rapidly making glucose available via glycogenolysis

adrenaline

describe the cell signalling pathway for adrenaline

1. adrenaline binds to complementary receptor on the cell-surface membrane of the liver cell

2. the binding or adrenaline causes the protein to change shape, activating a G protein

3. this activates the enzyme adenylyl cyclase

4. the activated adenyl cyclase converts AMP to cAMP

5. cAMP acts as a second messenger, binding to and activating many protein kinases via phosphorylation, amplifying the signal from adrenaline

6. protein kinases activate enzymes that catalyse the breakdown of glycogen into glucose

7. glucose moves out of liver cells by facilitated diffusion and into the blood through channel proteins

8. this increases the blood glucose concentration so that more glucose can be delivered to body cells for respiration

what protein is activated from the binding of adrenaline to the liver cell

G protein

what does the G protein activate

the enzyme adenylyl cyclase

what does adenylyl cyclase do

converts ATP into cAMP

how does CAMP act as a second messenger

is binds to and activates many protein kinases via phosphorylation, amplifying the signal from adrenaline

what do protein kinases do

they activate enzymes that catalyse toe breakdown of glycogen into glucose

how does glucose move out of the liver cells

facilitated diffusion

what is the cascade effect

one hormone molecule can generate multiple cAMP molecules. This effect amplifies at each stage, increasing the number of molecules involved.

what node sets the heart’s basic rhythm

the SAN

what two things can adjust the heart rate based on the body’s demands

the brain and the autonomic nervous system

what part of the brain acts as the control centre of heart rate

medulla oblongata

what receptors relay information to the medulla oblongata

baroreceptors and chemoreceptors

what are baroreceptors

blood pressure receptors

what are chemoreceptors

chemical receptors