Homeostasis And The Endocrine System, chapter 2, 5, 6 Flashcards
(97 cards)
1
Q
location
Hypothalamus
Endocrine glands
A
In the brain, just above the pituitary gland - specialised neurons
2
Q
function
Hypothalamus
Endocrine glands
A
control centre for endocrine system - produces hormones that regulate the pituitary gland
3
Q
hormones
Hypothalamus
endocrine glands
A
Releasing hormones (TRH, CRH, GnRH, GHRH)
Inhibiting hormones (somatostatin, dopamine)
4
Q
location
Pituitary gland
Endocrine glands
A
small pea like shape gland at base of brain. Anterior / Posterior
5
Q
function
Pituitary gland
endocrine glands
A
controls other enodcrine glands - releasing various hormones
6
Q
hormones
Anterior Pituitary gland releases
endocrine glands
A
- growth hormone
- adrenocorticotropic hormone
- thyroid stimulating hormone
- prolactin
(gonadotropins) - luteinizing hormone
- follicle stimulating hormone
7
Q
hormones
Posterior pituitary gland releases
Endocrine glands
A
- oxytocin
- antidiuretic hormone
8
Q
Homeostasis
A
maintain a constant/stable, internal environment or steady state
9
Q
endocrine system - 2 types of glands
A
- exocrine glands
- endocrine glands
10
Q
Exocrine glands
A
secrete into a duct that carries secretion to body surface or to one of the body cavities
- have ducts
- secrete fluid into body cavities or to body surfaces
11
Q
Exocrine gland examples
A
- sweat glands
- mucous glands
- salivary glands
- glands of alimentary canal
12
Q
endocrine glands
A
secrete hormones into extracellular fluid that surrounds the cells that make up the gland. secretion then usually passes into capillaries to be transported by blood
sometimes called ductless glands
- ductless
- secrete hormone into extracellular fluid surrounding gland
13
Q
endocrine glands - examples.
A
- pineal gland
- pituitary gland
- hypothalamus
- thyroid
- parathyroid
- thymus
- pancreas
- adrenal glands
- ovaries
- testes
14
Q
Hormones
A
- are chemicals secreted by endocrine glands transported throughout the body by the blood
- are chemical messengers secreted into the blood plasma by endocrine glands and affect target organs
15
Q
Two types of feedback loops
A
- Negative
- positive
15
Q
Negative feedback loops
A
- feedback that reduces the effect or eliminates the original stimulus
- involved in homeostasis
16
Q
Negative feedback loop examples
A
- gas concentrations
- thermoregulation
- osmoregulation
- blood sugar levels
17
Q
Positive feedback loops
A
- feedback that reinforces or amplifies the original stimulus
- not involved in homeostasis
18
Q
Positive feedback loop examples
A
- childbirth
- fever
- blood clotting
- breastfeeding
19
Q
two types of hormones
A
- steroid
- non-steroid (protein/amine)
20
Q
SRMERF acronym
whats it for
A
negative feedback loop
21
Q
SRMERF stand for
A
- Stimulus
- Receptor
- Modulator
- Effector
- Response
- Feedback
22
Q
SRMERF- Stimulus
A
change to the steady state
change in internal environment
23
Q
SRMERF - Receptor
A
sensor detect change
24
SRMERF - Modulator
- process info
- signal sent to control centre
25
SRMERF - Effector
- counteract stimulus effect
- organ or structure responds
26
SRMERF - Response
- action of effector
- physiological action counteracts stimulus
27
SRMERF - Feedback
- steady state restored
- system returns to stability, stopping response when balance
28
SRMERF example
Stimulus - increase body temp
Receptor - thermoreceptors in skin
Modulator - nerve impulse to hypothalamus
Effector - sweat glands
Response - sweating to cool down
Feedback - returned to balance
29
types of neurons
- 2 forms
1. functional
2. structural
30
# info about
Anterior lobe of pituitary gland
- produces its own hormones
- connected via blood vessels (infundibulum)
- releases numerous hormones
releases several hormones result of stimulation via tiny blood vessels of releasing factors from the hypothalamus
all hormones released from here stimulate the activity of a specific target organ, except growth hormone, which affects body tisssues in general throughout life
31
# info about
Posterior lobe of pituitary gland
- hormones produced in hypothalamus
- release stimulated by nervous conduction (infundibulum -- nerves)
- stores and releases hormones
- oxytocin and antidiuretic
'false gland' - doesnt produce hormones itself, stores and releases them
oxytocin and antidiuretic are made in special nerve cells in the hypothalamus
32
# Anterior lobe
Thyroid stimulating hormone
thyroid gland
33
# Anterior lobe
Thyroid stimulating hormone target organ- thyroid gland MAIN EFFECTS
(what is the effect??)
- stimulates growth of the thyroid gland
- stimulates the growth and release of hormones from the thyroid gland
34
Transmission of a nerve impulse
- resting potential
- action potential
- refractory period
- transmission of impulse along length of neuron
- transmission between neurons (synapses)
35
Infundibulum
connection between the hypothalamus and pituitary gland
36
hypothalamus - all in one
- base of brain
- responsible for regulation of number of homeostatic mechanisms
- sleep, thirst, temp, water balance, heart rate
- monitors levels of other chemicals in the blood
37
anterior lobe
| position
front lobe
38
posterior lobe
| position
rear - behind lobe
39
Adrenocorticotropic hormone (ACTH)
adrenal cortex
40
Follicle stimulating hormone (FSH)
ovaries or testes
41
Prolactin (PRL)
mammary glands
42
Luteinising hormone (LH)
ovaries or testes
43
Growth Hormone (GH)
all cells
44
Antidiuretic hormone (ADH)
kidneys
45
Oxytocin (OT)
uterus
mammary glands
46
Pineal gland
- deep in brain, decreases size after puberty, exact function uncertain
- secretes MELATONIN
47
Thyroid glands
- located in neck below larynx - 2 lobes - either side of the trachea
- secretes THYROXINE (T4) main, TRIIODOTHYRONINE (T3) & CALCITONIN
48
Parathyroid glands
- 4 - rear surface of thyroid gland
- secrete PARATHYROID HORMONE
49
Thymus
- located in chest, above heart, behind sternum
- larger in infants, shrinks after puberty
- secretes THYMOSINS
50
Melatonin
- regulation of sleep patterns
- melatonin - reduced in bright light
- melatonin - ^ in darkness
- some people take it artificially in order to treat insomnia or jet-lag
51
Thyroxine, Triiodothyronine
- T3 and T4 regulate body metabolism
52
Calcitonin
- reduces calcium in blood
- regulates calcium levels
53
Parathyroid hormone (parathormone)
- increases calcium in blood
- regulate phosphate levels
- increases calcium levels in the blood
- increases phophate excretion in the urine
54
Adrenal glands breaks into
- adrenal cortex
- adrenal medulla
55
Adrenal cortex
- 80% of adrenal gland
- produces hormones - slow, long lasting effect on body metabolism
- all hormones produced= steroids - from cholesterol
- collectively- corticosteroids
56
corticosteroids
collectively all of the hormones produced from the adrenal cortex
57
corticosteroids
| 2 components
- glucocorticoids
- mineralocorticoids
58
cortisol
- a glucocorticoid
- produced in response to stress
- promotes normal metabolism, helping body withstand stress and to repair damaged tissues
59
In stressful situations
- hypothalamus stimulates anterior lobe to release adrenocorticotropic hormone
- stimulates adrenal cortex to increase the production of glucocorticoids
60
glucocorticoids
- combat stress by raising blood sugar levels
- partly by inhibiting insulin and partly by gluconeogenesis
61
aldosterone
- a mineralocorticoid
- regulates water retention by acting on kidneys to regulate the distribution of sodium and other minerals in the tissues. increasing reabsorption of sodium and chloride ions, more potassium ions are lost in the urine
- acts on kidneys to reduce amount of sodium and increase amount of potassium in urine
62
Protein/amine hormones
| non steroid hormones
## Footnote
water soluble
- water soluble
- attached to receptor proteins on cell surface membrane
- activate secondary messenger within cell
- unable to diffuse across the cell membrane
- attach to receptor proteins in the membrane of target cell
- combination; hormone & receptor causes secondary messenger substances to diffuse through the cell and activate particular enzymes
for example: hormone insulin binds to recpetor protein, and this lelads to an increase in glucose absorption by the cell.
- protein & amine hormones are quick to cause a response but effect is short lasting
63
Steroid hormones
## Footnote
lipid soluble
- lipid soluble - do not dissolve in water
- pass across the membrane and bind with a receptor protein inside the cell
- activate genes controlling the formation of specific proteins
- in blood - bind to transport proteins, so can travel in the bloodstream
- reach target cells, steroid hormones separate from transport proteins and diffuse across the cell membrane
- inside the cell - combine with a receptor protein in the cytoplasm or nucleus
- hormone receptor complex activates genes controlling the formation of particular proteins.
- binds to the promoter section of a certain gene, stimulating or inhibiting transcription and therfore protein synthesis
slow effect but long lasting
64
Lipogenesis
the production of lipids/fats
65
Lipolysis
the breakdown of lipids/fats in the body
66
Gluconeogenesis
the process of producing glucose molecules from lipids and amino acids
67
Glycogenesis
the process whereby glucose molecules are chemically combined in long chains to form glycogen molecules
68
Glycogenolysis
the process of converting glycogen back to glucose
69
hyper
too much
70
hypo
too little
71
steroid hormones examples
oestrogen, progesterone, cortisol and aldosterone
72
Pituitary gland
lies under the hypothalamus, joined to the hypothalamus by the infundibulum. About 13mm in diameter, but vital to normal functioning of the body. Anterior and posterior lobes.
73
releasing factors
stimulate the secretion of a hormone
74
inhibiting factors
slow down the secretion of a hormone
75
hypothalamus connection to the pituitary gland
- infundibulum
- blood vessels - anterior lobe
- nerve fibres - posterior lobe (produced in hypothalamus)
76
which gland is the connection between both the endocrine and nervous system, and has roles in both systems
hypothalamus
77
hormone receptors
- are specific
- limited number of receptor proteins in cell membrane - limits rate of cells activity
- saturation can occur, once all receptor molecules are occupied by hormone molecules, the addition of more hormones does not produce any greater effect
- different cells have different types and numbers of receptor proteins. this is why there is variation in the sensitivities of cells to hormones and other substances
78
Enzyme amplification
- one hormone molecule can activiate/tirgger the production of thousands/millions of enzyme molecules
- a very small stimulus can produce a very large effect
79
hormone clearance
- once a hormone has produced the required effect, it must be turned off
- breaking down the hormone molecules
80
where are hormones broken down and excreted
- some are broken down in target cells but mostly in kidneys and liver
- excreted in either bile or urine
81
controlling hormone secretions
- to maintain homeostasis, hormonal secretions are generally regualted by negative feedback systems whereby the response produced by the secretion of the hormone is the opposite of the stimulus that caused the secretion
82
adrenal cortex releases
- cortisol
- aldosterone
83
adrenal medulla releases
- adrenaline
- noradrenaline
84
thymosins
influence the maturation of disease fighting cells called T-lymphocytes
85
what do hormones do or change
| LONG
hormones change the functioning of cells by changing the type, activities or quantities of proteins produced
- they can activate certain genes in the nucleus so that an enzyme or structural protein is produced
- change the shape or structrue of an enzyme - 'on' or 'off'
- change the rate of production of an enzyme or structural protein - changing the rarte of transcription or translation during protein production
- they can only influence cells that have the correct receptor for the hormone; therefore a hormone may affect; all cells of the body, only particular groups of cells (target cells), only particular organs (target organs).
86
which is the inner and outer in the adrenal glands
- adrenal cortex - outer
- adrenal medulla - inner
87
adrenaline (epinephrine)
- similar effect of sympathetic division of nervous system
- helps prepare body for reaction to a threatening situtation
- fight or flight response
88
noradrenaline (norepinephrine)
- similar to adrenaline
- increases rate and force of heartbeat
89
Pancreas
- 15cm long approx, just below the stomach and alongside duodenum
- exocrine and endocrine gland
exocrine
- secretes digestive enzymes into the small intestine through pancreatic duct
endocrine
- made up of clusters of special cells called islets of Langerhans which secrete 2 hormones [insulin and glucagon]
90
insulin
reduces the amount of glucose in the blood (blood sugar levels)
91
glucagon
increases the blood glucose level, also stimulates the breakdown of fat in the liver and in fat storage tissues
92
gonads
testes
ovaries
93
androgens (testosterone e.g.)
responsible for development and maintenance of the male sex characteristics, produced by testes
94
oestrogen and progesterone
stimulate development and maintenance of female sex characteristics. also regulate menstrual cycle adn involved in changes that occur during pregnancy
95
hormones produced by the gonads
- androgens
- oestrogen
- progesterone
96
other endocrine tissues
- stomach and intestine
- kidneys
- heart
- placenta
