13 Hormones and the Endocrine system

where are hormones destroyed

liver

properties of hormones

1. small, diffusible, soluble

   1. can diffuse out of cells that produce them, into blood capillary, out of the blood capillary into the cells of target organs

2 ways that hormones can affect activity

1. binds onto the cell surface of target organs and alter activity

2. diffuse into cells of target organs & alter activity

differences between endocrine and exocrine glands

endocrine

• gland secrete hormones directly into the blood stream

• no duct

exocrine

• glands secrete body fluids through a duct

function of the pituitary gland

controls and regulate production of hormones in other endocrine glands

secretory function of pancreas

endocrine

islets of langerhans

• alpha cells — glucagon

• beta cells — insulin

exocrine

pancreatic juice

hypothalamus secretory function

ADH (produced here)

pituitary secretory function

ADH (storage and secretion)

actually I can think of sm more functions but here we go

secretary function of ovaries

oestrogen and progesterone

secretory function of testes

endocrine

testosterone

exocrine

s3men (im doing this do not get flagged by the system. dear knowt, im just learning about bio!!)

why are oestrogen and progesterone and testosterone secreted

for sexual maturity and secondary sexual characteristics

how are the activities of target organs affected by insulin

1. increase in blood glucose levels

2. beta cells of islet of langerhans release more insulin

3. insulin transported to liver and muscle by blood

4. insulin makes liver cells and muscle cells more permeable to glucose molecules

5. glucose molecules diffuse into liver cells and muscle fibres and is converted to glycogen for storage / respiration / converted to fats

6. decrease in the blood glucose level to the normal concentration

how are the activities of target organs affected by glucagon?

1. decrease in blood glucose levels

2. alpha cells of islet of langerhans release more glucagon

3. glucagon transported to liver and muscle by blood

4. glucagon promotes the breakdown of glycogen to glucose molecules

5. increase in the blood glucose level to the normal concentration

what are the potential causes of diabetes mellitus

1. inability of pancreas to produce insulin

2. pancreas producing insufficient insulin

3. receptors on cell surface of target organs cannot recognise insulin

what is a symptom of diabetes mellitus

hyperglycaemia

treatment for diabetes

1. controlled diet low in carbohydrates

2. administer insulin into the body

   1. intravenously

   2. inhalation

can insulin be administered orally

no

insulin is made of protein so it may be denatured by the acid in the gastric juice. loses its 3D shape and no longer bind to the receptors of target organ cells to bring bout altered activity of target organs

insulin may also be digested by proteases in the alimentary canal. smiley, once digested, insulin loses its 3D shape and can no longer bind to receptors of target organ cells bring about altered activity of target organs

Stimulus for adrenaline

emotions such as fear, anxiety, and anger, and nervousness

Chemical: nicotine

Pathway for action of adrenaline

1. Stimulus: stress/anger/fear/anxiety/nicotine in blood

2. Detected by hypothalamus

3. Activates sensor neuroses in brain and an electrical impulse is generated

4. Transmission of electrical impulse along the neurons from brain to spinal cord

5. Transmission of electrical impulse to adrenal gland

6. Cells of adrenal glands release adrenaline

7. Adrenaline is transported by the blood to target organs to alter their activity to better respond to a fight or flight response

How does adrenaline target heart

Action: Makes heart beat faster, increasing blood pressure and increasing blood flow

Reasons: carries oxygen and glucose faster to muscles to increase rate of respiration

How does adrenaline target trachea & bronchus

Action: Dilate tranches and bronchus, increased rate & depth of breathing, allowing us to inhale and exhale more air

Reasons: more oxygen intake, more oxygen available to increase rate of respiration

How does adrenaline target iRis and pupil of eyes

Action: Circular muscles of iris relax and radial muscles of iris contract, causing pupil to dilate

Reasons: allows more light to enter the eye so that we can see clearer to better react to a situation

how does adrenaline target blood vessels

Action: Constrict skin arterioles, facial paleness, channel more blood to vital organs and skeletal muscles

Reasons: more blood chanelled to vital organs / skeletal muscles, more oxygen and glucose to vital organs and skeletal muscles to increase rate of respiration

How does adrenaline target liver

action: speed up the rate of glycogen break down to glucose

Reasons: increase blood glucose level, so more glucose is available to increase rate of respiration

How does adrenaline target muscles

Action: speed up the rate of glycogen (stored in muscle cells) to glucose

Reasons: more glucose available to increase rate of respiration especially in heart and skeletal muscles

How does the adrenaline target blood

action: increased rate of blood coagulation

Reason: increased rate of bloodletting in even of injury to minimise blood loss

Differences between nervou control and endocrine

1. Message: electrochemical VS chemical

2. Conductor: neurons vs blood plasma

3. Effectors: muscles or glands VS various organs

4. Type of response: short lived vs long / short lived

5. Type of control: voluntary vs involuntary

6. Duration of response: usually quick response vs usually slower response

Main 2 functions of adrenaline

1. Increased respiration to release mroe energy

2. Prepare body to respond better in a flight or fights situation

what is negative feedback’s basic principle

departure from a norm initiates changes which restore a system to the norm.

what does negative feedback d?

When there is a deviation from the norm/set point of a condition in the body (either increase or decrease), this serves as a stimulus for negative feedback. Negative feedback involves a corrective mechanism that brings about the opposite effect of the deviation in order to bring the conditions back to norm/set point.