Module 5.1.4 - Hormonal communication Flashcards
What are features of the hormonal system?
- transmission in blood
- slow transmission
- widespread response
- long lasting response
- may be permanent
- slow responses
What does the endocrine system do?
Reacts to change and uses hormones to bring about a response
What are the 2 hormone types?
Steroid hormones
Non-steroid hormones
What are steroid hormones?
Lipid soluble, pass through lipid soluble component of cell membrane and bind to receptors in cytoplasm or nucleus
What are non-steroid hormones?
Hydrophilic, cant pass directly through cell membrane, must bind to receptors on cell surface membrane instead
What are the adrenal glands?
2 small glands on top of each kidney, stress glands
What are the inside/outside tissues of adrenal glands made of?
Outside - gland tissue
Inside - nerve tissue
What is the inside and outside of the adrenal glands called?
Outside - cortex
Inside - medulla
What neurotransmitters does the medulla produce?
- adrenaline
- noradrenaline
What hormones does the cortex produce?
Androgens - sex hormone, makes oestrogen, particularly post menopause
Mineralocorticoids - aldosterone, regulates blood pressure and osmotic balance
Glucocorticoids - cortisol, regulates metabolic rate
What does the cortex secrete?
Steroid functions
What does the medulla secrete?
Neural function
Where is the pancreas found?
Behind stomach and in upper abdomen
What are parts of the pancreas?
Gallbladder, body, head, tail, duodenum
What does exocrine mean?
Releases enzymes into duodenum, such as lipase, amylase, protease
Gland has ducts to allow cells to secrete their products onto surface of target cells
What does endocrine mean?
Insulin and glucagon, produce chemicals (hormones) that regulate blood sugar
Glands don’t have duct system and releases products into bloodstream
What are Islets of Langerhans?
- small regions of endocrine tissue responsible for producing insulin and glucagon, lightly stained, larger spherical clusters
- alpha cells produce and secrete glucagon
- beta cells produce and secrete insulin
What happens when staining Islets of Langerhans?
- use differential staining technique
- beta cell stained blue
- alpha cells stained pink
What is glycogenesis?
Glucose -> glycogen
What is glycogenolysis?
Glycogen -> glucose
What is gluconeogenesis?
Amino acids - > glucose
How do high blood glucose levels go back to normal?
- increase is detected by beta cells in pancreas
- insulin is produced which increases respiration
- glucose is converted to glycogen and fats
- glucose is absorbed
- blood glucose levels fall back to normal
What is the normal blood glucose level?
90mg 100cm-3
How do low blood glucose levels go back to normal?
- fall detected by alpha cells in pancreas
- glucagon produced
- glycogen and amino acids converted into glucose
- uncontrolled quantity of glucose enters from intestine
Why does diabetes happen?
Pancreas doesn’t produce enough insulin or the body can’t effectively respond to insulin produced
What are the symptoms of diabetes?
- high glucose conc
- glucose in urine
- excessive need to urinate
- excessive thirst
- constant hunger
- weight loss
- blurred vision
- tiredness
Why is human insulin used?
Pure form, less likely to cause allergic reactions, high quantities produced, cheaper, no religious/ethical concerns over animal products
What is type 1 diabetes?
Autoimmune disease where body attacks beta cells in pancreas
- no insulin produced as a result
What is type 2 diabetes?
Condition based on lifestyle/diet
- beta cells in pancreas don’t produce enough insulin or not sensitive to insulin
- glycoprotein insulin receptor malfunctioning
- overweight
- high carb diet
What are some treatments for type 1 diabetes?
- insulin pump/injections
- pancreas transplant
- stem cell therapy
- glucose drinks/sweets
- balanced diet
What are some treatments for type 2 diabetes?
- exercise
- drugs
- insulin injections
- regular carb intake
How does the endocrine system respond to change?
- hypothalamus activates adrenal cortical system by releasing CRF
- pituitary gland secretes ACTH hormone
- ATCH arrives at adrenal cortex and releases around 30 hormones
How does the body respond to environmental changes?
Nervous and endocrine systems
What is the main response of adrenaline?
- to trigger liver cells to undergo glycogenolysis
- glucose released into bloodstream
- adrenaline is hydrophilic son cant pass through cell membranes
- adrenaline binds with receptors on surface of liver cell membrane
- trigger chain reaction inside cell
How does the neuronal system respond to change?
- hypothalamus activates sympathetic nervous system
- actives adrenal medulla which releases noradrenaline and adrenaline into bloodstream
- impulses activates glands and smooth muscle
What is the action of adrenaline process?
- hormone adrenaline approaches receptor site and activates adenyl cyclase
- adrenaline fuses to receptor site, activates enzyme inside cell
- activated enzyme converts ATP to cyclic AMP which acts as a second messenger that activates other enzymes that convert glycogen to glucose
What is the average human heart beat a minute?
70 times a minute at rest
What is heart rate controlled by?
Controlled by medulla oblongata in automatic nervous system
What is the medulla oblongata?
- 2 centres linked by sinoatrial node in heart by motor neurone
- impulses sent through sympathetic NS to increase heart rate by accelerator nerve
- impulses sent through parasympathetic NS to decrease heart rate by Vagus nerve
What are baroreceptors?
- detect changes in blood pressure
- in aorta, vena cava and carotid arteries
What are chemoreceptors?
- detect changes in levels of particular chemicals, pH
- in aorta, carotid artery and medulla
How do baroreceptors react to blood pressure increasing and decreasing?
- too high, impulses sent to medulla, parasympathetic neurones to SAN which decreases heart rate to normal levels
- too low, impulses sent to medulla, sympathetic neurones to SAN which increases heart rate to normal levels
What is hormonal control?
- fluctuates heart rate
- adrenaline and noradrenaline increases frequency of impulses produced by SAN
- speeds up heart rate
What is the process of chemoreceptors
- increased muscular/metabolic activity
- more CO2 is produced by tissues from increased respiration
- blood pH is lowered
- centre in medulla oblongata that speeds heart rate, increases frequency of impulses to SAN via sympathetic nervous system
- SAN increases heart rate
- increased blood flow removes CO2 faster
- CO2 level returns to normal
