Chapter 2 - Chemical Messengers Flashcards
exocrine glands
💚 secrete into duct
💚 duct carries secretion to body surface/body cavities
💚sweat glands
💚mucous glands
💚salivary glands
💚glands of alimentary canal
endocrine glands
💚 secrete hormones
💚 secrete them into extracellular fluid of cell that makes up gland
⚫ secretion then passes into capillaries/bloodstream
The Endocrine Glands
💚 hypothalamus 💚 pituitary 💚 pineal 💚 thyroid 💚 parathyroid 💚 thymus 💚 adrenal glands 💚 pancreas 💚 gonads
Hormones
💚 secretion of an endocrine gland
💚 proteins and amines
💚 steroid
💚 transported in blood
💚 can affect all cells of body or specific cells (target cells)/organs (target organs)
paracrines
💚 local hormones
💚 diffuse from cells to adjacent cells
💚 move through extracellular fluid (not bloodstream)
💚 for cells to communicate with other cells
protein and amine hormones
💚 attach to receptor proteins in MEMBRANE of target cell
💚 receptor proteins
☑️ are specific
☑️ only a certain amount
☑️ different cells have different types and amounts
💚 hormone ➕ receptor ➡️ secondary messenger substance
secondary messenger substance
☑️ diffuses through cell
☑️ activates particular enzymes
steroid hormones
💚 combine with receptor protein INSIDE CELL
(mitochondria, nucleus, other organelles)
hormone-receptor complex
☑️ activates genes
☑️ the genes control forming of particular protein
Hormones can…
1️⃣ activate certain genes in nucleus
2️⃣ change shape of enzyme (so it’s turned ON or OFF)
3️⃣ change rate of production of an enzyme
☑ done by changing rate of transcription/translation
enzyme amplification
💚 production of thousands of enzymes via bondage of hormone to receptor
hormone triggers cascading effect
➡️ no. of molecules involved increases x1000s for each step along metabolic pathway
💚 small stimulus = very large effect
hormone clearance
1️⃣ hormone molecules broken down
☑️ in liver/kidneys
☑️ some in target cells
2️⃣ degraded hormones secreted
☑️ bile
☑️ urine
Negative feedback system
💚 control of hormone secretions
☑️ regulates hormone secretions
☑️ response produced
➡️ opposite of stimulus that caused the secretion
☑️ regulating factors from hypothalamus
➡️ regulate function of pituitary
☑️ releasing factors from hypothalamus
➡️ stimulate release of a hormone OR inhibiting factors
Hypothalamus
💚 regulating and maintaining internal environment
☑️ body temperature
☑️ water balance
☑️ heart rate
💚 located at the base of the brain
Pituitary gland
💚 absolutely vital to internal functioning of body
💚 anterior and posterior lobe
💚 underneath and connected to hypothalamus
➡️ infundibulum
Anterior lobe of pituitary
💚 releases hormones that regulate bodily activities
💚 secretions controlled by releasing/inhibiting factors from hypothalamus
(extracellular fluid -> bloodstream)
💚 connected to hypothalamus by complex network of blood vessels
💚 FLATPEG
Hormones released by anterior lobe
💚 FHS 💚 LH 💚 ACTH (adrenocorticotropic hormone) 💚 TSH 💚 Prolactin 💚 Endorphins* 💚 Growth hormone (GH)
Posterior lobe
💚 not a true gland
➡️ release hormones produced by hypothalamus
💚 connected by special neurosecretory cells (neurons)
➡️ hormones produced in these cells
➡️ stored ready for release in posterior
↪️ then released into bloodstream
Hormones produced in posterior
💚 oxytocin
💚 anti-diuretic hormone
Pineal gland
💚 secretes melatonin
➡️ regulation of sleep patterns
➡️ stimulated by darkness and inhibited by light
💚 located deep inside brain, tiny
Thyroid gland
💚 in the neck
💚 two lobes on either side of trachea
💚 secretes thyroxine
➡️ controls body metabolism
Parathyroid glands
💚 four
💚 embedded in rear surface of lobes of thyroid
💚 secrete parathyroid hormone (PTH)
➡️ controls calcium and phosphate levels in blood
Thymus
💚 located in chest just above the heart, behind sternum
💚 secretes hormones called thymosins
➡️ maturation of T-lymphocytes
💚 shrinks after puberty
Adrenal glands
💚 one above each kidney
💚 each adrenal gland has an
☑️ adrenal cortex (outer)
☑️ adrenal medulla (inner)
Adrenal cortex
💚 produce corticosteroids
(20 different hormones, 2 main ones)
1️⃣ aldosterone
(kidneys - decr sodium/incr potassium in urine)
2️⃣ cortisol
(helps promote normal metabolism, withstand stress, repair)
Adrenal medulla
💚 adrenaline - sympathetic division, fight or flight
💚 noradrenaline - similar to adrenaline
☑️ increases rate and force of heartbeat
Pancreas
💚 just below stomach, alongside duodenum
💚 both and endocrine and exocrine gland
💚 exocrine
☑️ digestive enzymes
💚 endocrine
☑️ cells (islets of Langerhans/ pancreatic islets) secrete:
1️⃣ insulin - reduces glucose in blood
2️⃣ glucagon - increases glucose in blood
Gonads
💚 androgens
☑️ male sex hormones
☑️ testes
💚 oestrogen and progesterone
☑️ female sex hormones
☑️ ovaries
Other endocrine tissues
💚 stomach and small intestine
☑️ secrete hormones coordinating exocrine glands of digestive system
💚 kidneys
☑️ ethryropoietin (EPO)
➡️ stimulates production of RBCs by bone marrow
💚 heart
☑️ hormone that helps reduce blood pressure
💚 placenta
☑️ hormones maintaining pregnancy (development of foetus, stimulate mothers mammary glands)
Thyroxine
💚 increases metabolic rate
💚 target cells: most cells
💚 thyroid gland
Parathyroid hormone
💚 increases calcium levels in blood
💚 target cells: bones, kidneys
💚 parathyroid glands
Thymosins
💚 stimulates development and maturation of T-lymphocytes (immune)
💚 target cells: T-lymphocytes
💚 thymus gland
Aldosterone
💚 increases reabsorption of sodium ions,
increases excretion of potassium ions
💚 one of corticosteroids
💚 target cells: kidney
💚 adrenal cortex
Cortisol
💚 promotes normal metabolism
💚 helps body with stress
💚 promotes repair of damaged tissues
💚 target cells: most cells
💚 one of corticosteroids
💚 adrenal cortex
Adrenaline and noradrenaline
💚 prepares body for fight-or-flight responses
💚 reinforces effects effects of sympathetic nervous systems
💚 target cells: most tissues
💚 adrenal medulla
Insulin
💚 stimulates uptake of glucose (lowers BSL)
💚 target cells: most cells
💚 pancreas
Glucagon
💚 stimulates breakdown of glycogen and fat (increases BSL)
💚 target cells: liver and fat storage tissues
💚 pancreas
Androgens
💚 stimulate sperm production
💚 growth of skeleton and muscles
💚 male sexual characteristics
💚 target cells: many tissues
💚 testes
Oestrogens
💚 stimulate development of female characteristics
💚 regulate menstrual cycle
💚 target cells: many tissues
💚 ovaries
Progesterone
💚 regulates menstrual cycle
💚 regulates pregnancy
💚 prepares mammary glands for milk secretion
💚 target cells: uterus and mammary glands
💚 ovaries
Hormones of the anterior lobe
💚 FSH
☑️ ovaries: growth of follicles ☑️ testes: production of sperm
💚 Luteinising hormone
☑️ ovaries: ovulation, maintenance of corpus luteum
☑️ testes: secretion of testosterone
💚 Growth hormone
☑️ all cells
☑️ growth and protein synthesis
💚TSH (thyroid
