7 -Homeostasis Flashcards
1
Q
What does the endocrine system do?
A
Coordinates the bodies response to changes in the environment using hormones
2
Q
What are hormones?
A
Chemical messengers
3
Q
How do hormones travel?
A
In the bloodstream
4
Q
What are the different endocrine glands?
A
Thyroid Pituitary Ovaries Pancreas Adrenal Testes
5
Q
Where is the thyroid gland, what does it do?
A
Neck
Releases thyroxine
Regulates metabolism, heart rate, temperature
6
Q
Where is the pituitary gland, what does it do?
A
“Master Gland”
Brain
Linked to hypothalamus
Releases hormones in response to signals from hypothalamus
(Lots of these hormone trigger other glands to release hormones)
7
Q
what the ovaries gland do?
A
Produces oestrogen
Controls puberty
One of Main hormones in regulation of menstrual cycle.
8
Q
What does the pancreas do?
A
Produces insulin and glucagon
Regulate blood glucose levels
9
Q
What does the adrenal gland do?
A
Produces adrenaline - triggers ‘ flight or flight’ response when organism presented with a dangerous situation
2
Above both kidneys
10
Q
What do the testes do?
A
Produce testosterone
Controls puberty and sperm production
11
Q
What is the difference between the endocrine system and the CNS?
A
Endocrine
- Slower response
- However response can be long lasting
- Can act on large areas
- uses hormones
CNS
- rapid response
- electrical signals (by neurones)
- short response
- precise part of body
12
Q
What is the basic response order that the endocrine and CNS both follow?
A
Receptor cells
Coordination centres
Effectors
13
Q
What do receptor cells do?
A
Detect changes in the environment
14
Q
What processes information in a control system?
A
Coordination centre
15
Q
What are effectors?
A
Muscles/ glands
Bring about a response
16
Q
What do coordination centres do?
A
Process information
17
Q
What part of a control system bring about a response?
A
Effectors
Muscles/ glands
18
Q
What part of a control system detects changes in the environment?
A
Receptor cells
19
Q
What is the main hormone secreted by the thyroid gland?
A
Thyroxine
20
Q
What does thyroxine do?
A
Increases the basal ( resting) metabolic rate
21
Q
What does CNS stand for?
A
Central nervous system
22
Q
What type of loop is thyroxine regulated by?
A
Negative feedback loop
23
Q
What is the hormone TRH?
A
Thyrotropin- releasing hormone
24
Q
When does the hypothalamus release TRH?
A
When concentration of thyroid hormones in blood is low.
25
What does the hypothalamus’ release of TRH do?
Causes pituitary to release TSH
| - stimulates secretion of thyroxine by thyroid gland
26
What does TSH stand for?
Thyroid- stimulating hormone
27
What happens once the thyroxine levels have returned to normal or above normal?
TRH secretion is reduced
| This reduces TSH and thyroxin levels
28
What are all the hormones released when there is a low concentration of thyroid hormones?
- TRH (thyrotropin-releasing hormone).
- TSH (thyroid stimulating hormone)
- thyroxine
29
What does ‘ basel’ mean?
Resting
30
What hormone is secreted by the adrenal glands?
Adrenaline
31
When is adrenaline secreted?
Fear of stress moments
32
What is the nicknamed response for adrenaline
‘Fight of flight’
33
What does the ‘fight or flight’ response do?
Prepares the body to move and think quickly in response of danger
34
What does adrenaline do to blood glucose, how does it help?
Blood glucose
- liver converts stored glycogen back into glucose
- raises blood sugar levels
35
What does adrenaline do to heart rate and blood pressure? how does it help?
increase heart rate and blood pressure
- vasoconstriction
- increase blood flow to muscles
36
What does adrenaline do to the lungs? How does it help?
Enlarges lungs
Alters metabolism
- boosts delivery of oxygen and glucose to brain and the muscles
37
What three things does adrenaline effect?
Lung volume
Heart rate and pressure
Blood glucose
38
What gland secretes adrenaline?
Adrenal glands
39
What are male secondary sex characteristics?
-Testosterone rises
stimulates sperm production
-Hair growth
-Voice deepens
40
What are female secondary sex characteristics?
- oestrogen hormone rises
Triggers menstrual cycle
- hair
- breasts enlarge
41
What are secondary sex characteristics caused by?
Puberty
42
What four hormones control the menstrual cycle? (Endocrine)
- FSH (follicle Stimulating Hormone
- Oestrogen
- LH (Luteinising hormone)
- progrestrerone
43
Is a female born with all her eggs?
Yes but only on egg will mature each month
44
What does the menstrual cycle involve?
Maturation and release of an egg
45
What hormone is released by pituitary gland and causes egg in ovary to mature?
FSH
Follicle stimulating hormone
(Also stimulates production of oestrogen)
46
What hormone causes production of oestrogen?
FSH
| Follicle stimulating hormone
47
What does the hormone oestrogen do?
Development of thick spongy uterus lining
Stimulates LH
(Luteinising hormone)
Stops production of FSH
48
Where is oestrogen released?
Ovaries
49
Where is LH produced?
Pituitary gland
50
What does LH do?
Ovulation
| - Stimulates release of a mature egg on Day 14 of menstrual cycle
51
What does progesterone do?
Maintains lining of uterus in days 14-28
Stops release of LH and FSH
52
What happens when progesterone levels drop?
Triggers breakdown of uterus lining
53
What is stage 1 of the menstrual cycle?
(days 1-4): The uterus lining breaks down, resulting in a ‘period’.
54
What is stage 2 of he menstrual cycle?
(days 4-14): The uterus lining starts to build up again into a thick, spongy layer full of blood vessels.
55
What is stage 3 of menstrual cycle?
Stage 3 (day 14): Ovulation happens. This is when an egg is released from one of the ovaries.
56
What is stage 4 of menstrual cycle?
(day 15-28): The uterus lining is maintained, which means that it is now ready for the arrival of a fertilised egg (which will eventually grow into a baby). If no fertilised egg is attached to the uterus lining, the lining breaks down and the cycle begins again.
57
What are the two main types of contraceptive pills?
-Combined pill
(Contains oestrogen and progesterone)
-Progesterone- only pill
58
What does the combined pill do?
Daily intake
Enough oestrogen builds up
Inhibits production of FSH- no eggs mature
59
What does the progesterone only contraceptive pill do?
-Stimulates production of thick sticky mucus
(Difficult for sperm to penetrate)
- inhibits release of FSH = eggs don’t mature
- as effective as combined pill, fewer side effects
60
What are three other ways of preventing contraception?
implant
Patch
Injection
61
What is the contraceptive implant
- Lasts for 3 years
- Inserted under skin
- Continuously releases small amount of progesterone
62
What does the contraceptive patch do?
- placed on skin
- changed once a week
- steadily releases progesterone
63
What does the contraceptive injection do?
-Contains progesterone -last up to 3 months
64
Which hormone is released by the contraceptive patch, injection and implant?
Progesterone
65
What contraceptive insertion methods are there
- intrauterine devices (IUDs)
| - diaphragms
66
What do Intrauterine devices (IUDs) do?
- know as the coil
- t- shaped
- inserted into uterus
- prevents implantation of an embryo
- some release progesterone
67
What do diaphragms do?
- shallow plastic cup
- inserted in vagina pre sex
- sits at entrance to uterus
- prevents sperm from reaching egg
- some covered in spermicide (murders sperm)
68
What do contraceptive pills do?
Reduce a woman’s fertility and chance of pregnancy
69
What do condoms protect against?
STIs ( sexually transmitted infections
E.g... chlamydia, gonorrhoea and HIV
70
What does spermicide do?
Kills sperm
| Often on condoms
71
What do condoms prevent?
Sperm from entering female during ejaculation
72
What are natural methods of preventing contraception?
Abstinence
| Timing
73
How does timing work as a contraceptive method?
- females body temp rises during ovulation
- avoid sexual intercourse
- sperm can last for 6 days in woman’s body
- not reliable method
74
What is the only truly effective method of avoiding pregnancy?
Abstinence
75
What permanent contraceptive procedures are there?
Sterilisation
Male = sperm ducts cut so sperm not released on ejaculation
Female= Fallopian tubes cut, egg cant reach uterus
76
What is a hormonal reason for a woman being infertile?
Some women do not have high enough levels of FSH to stimulate (lead to) the maturation of their eggs
77
What drugs help women who do not have enough FSH to become fertile?
- Clomifene
| - In vitro fertilisation
78
What does clomifene do?
- Triggers ovulation
- Increase in release of FSH
- Helps follicle mature into egg cell
- increase concentration of LH
79
What is IVF?
- In vitro fertilisation
- FSH and LH stimulat growth of lots of eggs
- egg collected
- fertilised in lab dish , fathers sperm
- grow into embryos
- implanted into woman’s uterus
80
What drugs are used to stimulate large numbers of eggs in IVF
FSH and LH
81
What is a follicle?
Small sac of fluid which contain immature eggs
Found outside layer of ovaries
Ruptures and releases egg (ovulation)
82
What would increase the chance of pregnancy in IVF?
Implanting two embryos
83
What is the point of fertility treatments?
offer fresh hope to couples who are unable to conceive naturally
84
What are the disadvantages to fertility treatments?
- stress
- expensive
Not guaranteed to work, multiple attempts cost
- multiple pregnancies
Can put both mother and children at risk
85
What is a common side effect of any cancer?
Weight loss
86
What is homeostasis?
All the processes that happen in a cell or organism to maintain optimal conditions
87
What is homeostasis needed for?
Respond to changes in the internal and external environment
| - enzymes function well, not denatureing
88
What happens if a enzyme denatures?
Their ability to catalyse metabolic reactions is reduced
89
Why must humans regulate their body’s internal conditions
Make sure enzymes and cells function well
90
What internal conditions need to be regulated in our bodies?
```
Carbon dioxide levels
Water levels
Urea (concentration in urine)
Internal body temperature
Blood sugar levels
```
91
What does FSH do ?
follicle stimulating hormone (FSH) causes the maturation of an egg in the ovary
92
What does LH do?
luteinising hormone (LH) stimulates the release of the egg
93
What does oestrogen do?
oestrogen is involved in repairing and thickening the uterus lining,
94
What does progesterone do?
progesterone maintains the uterine lining
95
What two types of response do control systems use?
Nervous and chemical
96
What are the three parts of a coordination system?
Coordination centre
| Receptor effector
97
What is negative feedback?
- internal condition changes
- no longer optimal internal conditions
- body works to counteract change
98
What is the word for the control of body temperature?
Thermoregulation
99
What heat do our bodies want to be kept as close as possible to?
37 degrees celcius
100
What detects changes in temperature?
Receptors
101
What do receptors relay information to?
The CNS
102
What does the CNS do after being given information?
Allows effectors to respond
103
What are effectors?
Muscles or glands
104
What is the name of the receptor in the thermoregulatory part of our brain?
Hypothalamus
105
What does the hypothalamus do as a thermoregulatory centre?
- blood flows through brain
| - monitors internal body temperature
106
What receptors monitor temperature at the surface of our body?
The skin
107
What is 37 degrees Celsius
Ideal human body temperature
108
What does the body do in response to being too hot?
- sweat
- hairs lie flat
- vasodilation
Allows more blood to enter capillaries that pass close to skins surface
109
What does the body do in response to being too cold?
```
- shivering
Muscle contractions increase
- hairs stand on end
- Vasoconstriction
Reduces blood flow to capillaries
```
110
What does ‘Vaso’ mean?
Something related to blood vessels
111
What is vasodilation?
- If we are too hot, then the muscular walls of blood vessels relax
- Blood vessels dilate to allow more blood to enter capillaries.
112
What is vasoconstriction?
- If we are too cold, then the muscular walls contract.
| - Blood vessels constrict to reduce blood flow in capillaries
113
What does thermoregulation control?
Body temperature
114
Where are our sweat glands?
Middle layer of skin
| - Demis
115
What is the outer layer of our skin?
Epidermis
116
How does sweating work?
- Heat energy transferred to water in sweat
- enough energy = evaporation
- takes heat energy with it
- lowers average temperature of the body
117
What is shivering?
Muscles contracting rapidly and automatically
118
How does shivering warm us up?
- muscle contraction
- needs energy
- generated through respiration
- respiration produces heat
- warms us up
119
What are hairs on our body controlled by?
Hair erector
120
Where are hair erectors?
Dermis
121
What is the dermis?
Middle layer of skin
122
What happens to the hair erector muscle when we are too hot?
- Muscle relaxes
| - hair lies flat
123
What happens to the hair erector muscle when we are too cold?
-Muscle contracts
- hair stands up on end
Pulls skin giving goosebumps
124
Why do our hairs stand on end when we are cold?
Traps an insulating layer around body
125
How do ducks lose heat?
From their feet
126
How do have ducks evolved to reduce heat loss?
- decreased blood flow to feet
| - blood is cooled so less heat conducted away by the cold water
127
What happens I’d blood glucose levels are too high?
- negative impact on osmosis
| - affects concentration gradients
128
What happens I’d blood glucose levels are too low?
- glucose important for respiration
- respiration releases energy needed by every living cell
- not enough glucose= not enough energy for organism
129
What is glucose fuel for?
Respiration
130
How does the body detect if blood glucose is at the right level?
Blood flowing through pancreas
131
When will our bodies try bring our glucose levels back to normal?
If glucose levels are too high or low
| - negative feedback loop
132
What happens if blood glucose is too high?
Pancreas releases insulin into bloodstream
133
What happens if blood glucose is too low?
Pancreas releases glucagon into blood stream
| Glucose gone = glucagon
134
What detects the presence of insulin?
The liver and muscle tissues
135
What happens when insulin is detected?
- Liver and muscle tissues
| - convert excess glucose into glycogen
136
When does the production of glycogen stop?
Pancreas detects normal level of blood glucose concentration
137
What detects the presence of glucagon?
Liver
138
What happens when glucagon is detected?
- Liver
- converts stores of glycogen back into glucose
- released in bloodstream
139
When does the production of glucose from glycogen stop?
Pancreas detects normal level of blood glucose concentration
140
What is glycogen?
- form of glucose
- insoluble
- can be stored for later use
141
What is the optimal blood glucose range for humans?
6-8 mmol/dm 3
142
What are people suffering from diabetes unable to control?
Blood glucose levels
143
What is type 2 diabetes?
- still produce insulin
| - body’s no longer respond to it
144
What is type 1 diabetes?
- unable to produce enough insulin
145
When does Type 1 diabetes develop?
During childhood
146
What causes type 1 diabetes?
Don’t know
| Think its body’s immune system attacking pancreas cells
147
What is the treatment for type 1 diabetes?
- Inject insulin when blood glucose too high
| - manage diet, exercise regularly
148
Whalen does type 2 diabetes develop?
Later in life
| - old age & overweight are primary risk factors
149
What is the treatment for type 2 diabetes?
- injecting insulin wont help
| - manage diet and exercise, keep blood glucose levels steady
150
What are major risk factors for type 2 diabetes?
Old age
| Obesity
151
Can type 2 diabetics produce insulin?
Yes
| - their body’s don’t respond to it
152
Why must water levels be kept relatively constant in the body?
Control amount of water and ions diffusing in and out of cells
153
What can disrupt water level balance?
Eating too much salt
Illness
Sweating
Exhalation
154
What does eating too much salt do to disrupt water levels?
Can make blood ion concentration too high
155
What does illness do to water levels?
Can cause:
- fever
- vomiting
- diarrhoea
Can result in dehydration
156
What is dehydration
Blood’s water concentration too low
157
What does sweating do to water levels?
- water
- ions
- urea
Lost in sweat
158
What does exhalation do to water levels?
Water in lungs leaves body in persons breath
159
What is a hypotonic solution?
- higher water concentration
- lower ion concentration
Than cells
160
What happens if the blood becomes hypotonic?
Cells gain water by osmosis and burst
161
What is a hypertonic solution?
- lower water concentration
- higher ion concentration
Than cells
162
What happens if the blood becomes hypertonic?
Cells lose water by osmosis and shrink
163
What is an isotonic solution?
- same water and ion concentration as cells
164
What type of water solution does the blood want to be?
Isotonic
165
How does the blood remain isotonic?
Homeostasis
| - regulates blood water and ion concentrations
166
What do the kidneys control?
Water and ion levels in the blood
167
What must the blood’s ion levels be kept constant?
Control osmosis and diffusion between cells in body
168
What monitors the volume of water in the blood?
Hypothalamus
169
What are the main functions of the kidney?
- filter blood
- produce urine
Remove unwanted substances such as urea
- remove excess water
170
Why must Water levels in the body must be kept relatively constant?
control the amount of water and ions diffusing in and out of cells.
171
Why does urea need to be removed from the body?
- It is toxic
| - too much in bloodstream- harm cells and tissues
172
When is urea formed?
- digestion of protein
- excess amino acids
- cant be stored in body
173
What process do amino acids undergo?
Deamination
174
Where does deamination occur?
Liver
175
What is the waste product of deamination?
Ammonia
176
What happens to ammonia in he body?
- Converted into urea
| - excreted from body as urine
177
What happens if there is too much urea in the bloodstream?
Causes harm to cells and tissues
178
What are the millions of very small structures in the kidney called?
Nephrons
179
What are the two stages of urine production?
- ultrafiltration
| - selective reabsorption
180
Where do the two stages of urine production take place?
Nephrons in the kidney
181
What happens in ultrafiltration?
- blood capillaries form a glomerulus (knotted cluster)
- blood filtered
- Water, urea and salts move into nephron tubule
- blood cells and proteins remain in blood
Too big to move across capillary walls
182
Where are glomerulus’ found?
Inside the Bowman’s capsule
183
What happens in the bowman’s capsule?
Filtering occurs
184
From the bowman’s capsule, where does all the waste go?
Filtered from glomerulus to the
| Proximal convoluted tubule / nephron tubule
185
What waste is filtered across from the glomerulus?
Water
Urea
Salts
186
What remains in the blood and is not filtered by the glomerulus?
Proteins and blood cells
187
Why do proteins and blood cells remain in the blood?
Too big to move across the capillary walls
188
What happens during selective reabsorption in the nephron?
- useful substances reabsorbed from tubule back into bloodstream
- leaves all waste in tubule
- mixture forms urine
- collected by kidneys
- travels to bladder
- stored
- excreted
189
What are some of the useful substances reabsorbed during selective reabsorption?
Glucose and some water
190
What are two stages in the process of urine production occurring in the nephron?
Ultrafiltration
| Selective reabsorption
191
What is ADH?
Anti - diuretic hormone
192
What does diuretic mean?
Causing increased passing of urine
193
What monitors the volume of water in the blood?
Hypothalamus
194
What happens if the body has too much water?
- hypothalamus—- pituitary gland
| - stop releasing ADH
195
What does stopping the release of ADH do?
Reduces permability if kidney tubules
- less water reabsorbed into bloodstream
= large volume of dilute urine
196
What happens if the body has too little water?
- hypothalamus triggers pituitary
| - releases ADH
197
What does the release of ADH do?
- increases permeability of the kidney tubules
- more water reabsorbed back into bloodstream
= small volume of concentrated urine
198
Which hormone helps to control the volume of water in urine?
Anti- diuretic
199
What is urea converted from?
Ammonia
200
What is a treatment for kidney failure?
Dialysis
201
How does the dialysis machine (simply ) work?
- patient linked up to dialysis machine
- blood flows into machine
- machine fluid diffuses good things across to blood
- bad things from blood into machine fluid
202
What does the dialysis machine fluids contain?
Optimum concentrations of
Salts ( e.g. sodium &potassium ions)
Glucose
203
How does the dialysis machine sort out stuff in the blood?
- patients blood passes over partially permeable membrane
- dialysis fluid other side of membrane
- concentration gradient established
- diffusion
204
What diffuses from the blood to the dialysis fluid?
Excess ions and urea
205
What diffuses from the dialysis fluid into the blood?
Salts and glucose
206
What is a dialysis machine designed to replicate?
Kidneys function
207
What are the disadvantages of dialysis?
- lasts 3-4 hours
- needed 3 times a week
- increase risk of blood clots and infections
- expensive process
208
What are the advantages of dialysis?
- life saving process
| - gives patient more time to find a kidney donor
209
Wha happens if the concentrations of urea and salts are too far away from optimum?
May cause tissue damage
210
How many kidneys do humans have?
2
211
Why can kidneys be donated from a live donor?
Humans can survive with only one kidney
212
If a patient receives a donated kidney, what drugs do they need to take?
Immunosuppressants
| - rest of lives
213
What do immunosuppressants do?
Suppress immune system
| - stop it destroying foreign cells of transplanted kidney
214
Where do kidney transplants often come from?
| - why?
Close relatives
| - higher chance of tissue match
215
What are the advantages of having a kidney transplant?
- does not need dialysis treatment (time consuming)
| - cheaper than dialysis in long run
216
What are the disadvantages of kidney transplants?
- kidney may be rejected from body
- long waiting lists
- often have to are immunosuppressants
(Can make patient prone to other infections)
217
Where are adrenal glands situated?
Above the kidneys
218
What does FSH do?
Causes egg in ovary to mature
| Stimulates production of oestrogen
