The Endocrine System Flashcards
What are hormones
Chemical messengers
Where are hormones made
Endocrine glands
Hormones go to ——— for a response
Target organs
Homeostasis
To maintain a constant internal environment
What does homeostasis allow for
Helping the body cells to work at their optimum
How is brain involved in homeostasis
Coordinates responses to internal and external stimuli
How is the lungs involved in homeostasis
Controls amount of O2 and CO2 in blood
How are the muscles involved in homeostasis
Can respond to environment and blood sugar
How is the skin involved in homeostasis
senses external environment and controls body temperature
How is the pancreas involved with homeostasis
Can increase/decrease amount of glucose in blood
How is the kidney involved with homeostasis
Can control amount of water in blood
How are hormones transported
They are secreted into the blood and diffused out of it to the target cells of the target organs
Nervous system vs Endocrine system
Nervous system is very fast as electrical impulses travel through the axon for a short time at a specific place.
Endocrine system is much slower and is transported through the blood for a long time all over the body
What is your thyroid gland and what does it do
Secretes thyroid hormones - which controls the speed at which bodies chemicals functions proceed
How is the thyroid hormones made
Takes iodine from food and converts it to thyroxine by combining it with amino acid tyrosine
Hypothyroidism
Where the thyroid gland doesn’t produce enough thyroid hormones
Hyperthyroidism
Where the thyroid gland produces too much of the thyroid hormones
What are adrenal glands and what do they do
Adrenal glands are small glands on top of your kidneys that produce hormones that help regulate metabolism, immune system and respond to stress
Adrenaline
Adrenaline is used in times of stress to prepare itself for intensive action
What happens when you have adrenaline
Your eyes dilate, heart + breathing rate increases, blood diverts away from the organs (digestive) to your muscles
If a factor in the environment increases,
The system changes to reduce it back to normal
If a factor in the environment decreases,
The system changes it increase it back to normal
How long does a menstrual cycle last
28 days
Why does the lining of the uterus start to thicken
To receive a fertilised egg
After 14 days …
The egg is released from the ovary - called ovulation
If egg is fertilised
May implant the uterus lining - protected and receives nutrients and oxygen
If egg not fertilised
Is removed from the body - called periods
How is the menstrual cycle controlled
By 4 hormones; follicle stimulating hormones, oestrogen, luteinising hormone, progesterone
What does the ovary do?
Eggs mature and are stored here
What does the Fallopian tube do?
Where the egg is fertilised before travelling along the tube to uterus
What does the uterus do?
The foetus develops here
What does the cervix do?
Entrance to the uterus
What does the vagina do?
Receives sperm from the penis during sexual intercourse
Follicle stimulating hormone to where and why
Secreted by the pituitary gland - travels to egg to mature
Oestrogen goes to where and why
Secreted by ovaries - causes the uterus lining to build up
Luteinising hormone where and why?
When the hormone reaches the peak in the middle of the cycle - ovulation is triggered
Progesterone where and why?
Maintains uterus lining - levels remain high throughout pregnancy
Techniques to prevent pregnancy
Contraceptions
Non hormonal techniques
Barrier methods to prevent sperm contacting egg. Also, uses physical devices that release chemical compounds to kill sperm cell and prevent implantations
Hormonal techniques
Use hormones to disrupt normal reproductive cycle
Condoms and diaphragms (cervical caps)
Placed over area to prevent sperm cells entering
95-98%
92-96%
Intrauterine device
Inserted into the uterus - released copper that kills sperm cell surviving in uterus = over 99%
Oestrogen and progesterone pill
Thickens mucus from cervix - stopping sperm from reaching an ovum = 99%
Progesterone (same for intrauterine system)
Thickens mucus from the cervix - stopping sperm from reaching an ovum. Also thins uterus lining preventing implantations = over 99%
Tropism
When plants detect stimuli in their environment and respond by growing in a particular direction
Phototropism
Growing towards the light
Gravitopsim
Growing in the same direction as gravity
Auxin
The plant hormone that enables a plant to grow towards or away from a stimuli
How do plants respond to light
Auxin moves to side without light and there is a build up of it on the shaded side. The cells respond by elongating and increases length of the shoot, so shoot bends towards the light.
How do roots respond to gravity
The root grows more on the side with the least amount of auxin, making it bend and grow down towards gravity
How do shoots respond to gravity
The shorts grow more with the side of most auxin making it bend and grow up away from gravity
Ethene
Causes plants to ripen by stimulating the conversion of starch into sugar (only hormone in gas form)
Gibberellins
Promotes growth of stem elongation. Also end dormancy period of seeds and buds - shoots and flowers open
Killing weeds
The auxin weed killer makes them grow too fast. This rapid uncontrolled growth kills the plant
Promoting root growth
Cut off a plant shoot, dip it in auxin (rooting powder) and develops to produce identical plants
Delaying ripening
Auxin is sprayed on fruits to delay ripening to be collected at same time
Ripening fruits
Ethene is sprayed on fruits so they ripen quicker
Producing seedless fruits
Auxin applied to unpollinated flowers so the plants produce them parthenocarpic
Controlling dormancy
Spray gibberellins or auxins to germinate on winter so they last until ideal conditions
What is a clinostat
A rotating device to reduce the effect of gravity on plant and experiment which is measuring phototropism
What is TRH
releasing hormone which stimulates TSH
- so if thyroxine is low, both will increase to increase back to normal