educake = Homeostasis and the nervous system; The human endocrine system: blood glucose levels and Human reproduction Flashcards
What type of cell in the nervous system detects a change in the environment?
Receptor cells
What is the word for a change in the environment that a receptor cell responds to?
A stimulus
What is the name of the system that enables humans to react to their environment?
nervous system
What is the word for an organ or tissue that brings about the response in a reflex action?
An effector organ
Effectors can be either…
muscles or glands.
Where in the nervous system is information from receptors taken to for processing?
the central nervous system
e.g. brain and spinal cord
what’s the function of the brain?
to process information and coordinate a response.
what internal conditions does the body need to maintain (6-4)
- Temperature (around 37°C)
- Blood glucose levels
- Water balance
- pH levels (e.g., in blood and tissues)
- Ion (salt) balance
- Oxygen and carbon dioxide levels
Which system is able to respond to change faster: the nervous system or hormonal system?
The nervous system
because it uses electrical impulses to transmit signals, which allow for rapid communication.
Which system has longer lasting effects: the nervous system or hormonal system?
The hormonal system
because hormones are released into the bloodstream and they remain in the blood until broken down
causting them act slower but have longer-lasting effects
homeostasis definition
is the regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external conditions.
This includes regulating factors such as temperature, pH, blood pressure, and water balance.
why does out body go through homeostasis?
to ensure that cells and enzymes have the right optimal conditions to work properly
what are the three main components in an automatic control system?
receptors - detects the change
coordination centres - interprets that change and figures out what to do
e.g. brain and spinal cord
Effectors - carry out the change
e.g. muscles (contracts )and glands (releases hormones)
Negative feedback
Negative feedback is a loop process where the body responds to a change by reversing it, helping to maintain stable conditions.
e.g. cold person will shiver however when the person gets too hot then they will sweat. and shiver again if cold ect…
What is the role of a coordination centre?
coordination centres - receive and interpret signals from receptors that change and figures out what to do
e.g. brain and spinal cord
What is the role of a effector?
Effectors - carry out the change
e.g. muscles (contracts )and glands (releases hormones)
What is the role of a receptor?
Detects changes in the internal or external environment
Where are the coordination centres located in the body?
brain and spinal cord
Name the two types of effectors and state what they do.
Muscles - contract when stimulated,
glands - release hormones
What passes along nerve cells?
Electrical impulses
What is the gap between two neurones called?
Synapse
What is released across a synapse?
a chemicals called a neurotransmitter
What is the role of a receptor?
To detect a stimulus
What is the role of a sensory neurone?
To transfer a signal from a receptor to the CNS
What is the role of a motor neurone?
To transfer a signal from the CNS to an effector
What is the role of a relay neurone?
To transfer a signal from a sensory neurone to a motor neurone
What is a reflex?
An automatic response to a stimulus
The pathway of a reflex arc (7)
stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response
Why are reflexes important?
They protect us from harm
What type of structures secrete hormones?
Endocrine glands
Endocrine glands, found in many parts of the body, secrete hormones in response to a stimulus.
Which hormone lowers blood sugar levels when they are too high?
insulin
The organ that a particular hormone acts on is known as the __________ organ. What one word completes this sentence?
target
target organs
Target organs are specific organs or tissues that a hormone affects. They have receptors that the hormone binds to, allowing it to exert its effects on that organ or tissue.
What type of molecule is the hormone insulin made from?
proteins
What type of protein is a chemical messenger that travels in the blood?
A hormone is a protein that acts as a chemical messenger. It travels in the blood from where it is made to where it is used.
what’s an hormone
A hormone is a chemical messenger produced by glands that travel through the bloodstream to target organs or tissues, where they regulate various physiological processes such as growth, metabolism, and mood.
Name the organ that monitors the concentration of glucose in the blood.
pancreas
what’s the role of insulin?
Insulin is a hormone that controls the concentration of glucose in the blood, maintaining it at a constant level.
what’s the role of the pancreas?
The pancreas produces:
Digestive enzymes (e.g., amylase, lipase, protease) to break down food in the small intestine.
Hormones like insulin and glucagon to regulate blood sugar levels.
Name the glucose-regulating hormones produced by the pancreas.
One hormone is called insulin and the other glucagon.
what is type 1 diabetes
a condition where the pancreas produces little or no insulin
how to treat type 1 diabetes
- injecting insulin into their body
- following a healthy diet
- exercising regularly
- monitoring glucose levels
what produces insulin?
the pancreas
Where is adrenaline produced?
adrenal glands
Where is thyroxine produced?
thyroid gland
what does thyroxine do?
regulates the body’s metabolism, growth, and energy production. It controls the speed at which cells work, affecting processes like heart rate, body temperature, and protein synthesis.
how are hormones transported around the body ?
in the blood
What type of tissue produces hormones?
Specialised tissue called glandular tissue produces hormones.
If people with diabetes are not treated, what problem with their blood glucose level are they most likely to have?
If a diabetic person does not receive treatment, their blood glucose levels will be too high as their body cannot control blood glucose concentration by itself.
People with untreated diabetes are more likely to get infections because high blood sugar levels can weaken the immune system making it harder to fight off bacterial and fungal infections.
Carl is diabetic. He injects insulin in the morning but then doesn’t have time for lunch. What problem is most likely to occur with his blood glucose level?
The insulin Carl injects in the morning will lower his blood glucose concentration. If he does not eat any lunch, his blood glucose concentration will become too low.
Name the hormone that increases the heart rate.
Adrenaline
what’s Adrenaline
Adrenaline is a hormone that circulates around the body in the blood and causes the heart rate to increase.
When glucagon acts upon liver cells, it stimulates the cells to convert glycogen into a soluble carbohydrate that is then released into the bloodstream. What is the name of this carbohydrate?
The hormone glucagon converts glycogen into a soluble carbohydrate called glucose. This is then transported around the body in the blood vessels.
What is sometimes called the “master gland”
pituitary gland
why is the pituitary gland called the “master gland”
because it controls the functions of many of the other endocrine glands.
Thyroxine is controlled by what type of feedback?
negative feedback.
The amount of thyroxine circulating in the blood is kept within narrow limits by negative feedback.
Protein present in urine tells us that…
Protein present in urine suggests kidney problems.
Dark urine tells us that…
Dark urine indicates dehydration from exercise.
Presence of sugar in the urine tells us that…
Presence of sugar in the urine is a sign of uncontrolled diabetes.
Almost clear urine tells us that…
Almost clear urine indicates high water intake.
what does glucagon do?
it increases blood glucose levels by causing the liver to break down glycogen into glucose and release it into the blood.
Where in the body is the hormone glucagon produced?
pancreas
In the menstrual cycle, the release of an ovum is called what?
ovulation
What is the monthly shedding of the lining of the womb in the menstrual cycle called?
menstruation or a period
The lining of the uterus needs to be thick after ovulation so that what can implant?
a fertilised egg, called a zygote, sinks into the thickened lining of the uterus.
What does FSH stand for?
Follicle Stimulating Hormone
What does LH stand for?
Luteinising Hormone
FSH (4)
- follicle-Stimulating Hormone
- produced in the pituitary gland
- causes an egg to mature in one of the ovaries in a structure called follicle
- stimulates the ovaries to produce oestrogen
oestrogen (3)
- produced in the ovaries
- causes the lining to grow
- stimulates the release of LH (which causes the release of an egg) and inhibits release of FSH.
LH (3)
- Luteinising Hormone
- Produced by the Pituitary gland
- Stimulates the release of an egg at day 14 (ovulation)
Progesterone
- Produced in the ovaries by the remains of the follicle after ovulation.
- maintains the lining of the uterus during the second half of the cycle. When the level of Progesterone falls, the lining breaks down
- Inhibits the release of FH and FSH.
What gland secretes FSH and LH?
the pituitary gland situated in the brain.
name 4 hormones that is involved in the menstrual cycle.
- hormone (LH)
- follicle stimulating hormone (FSH)
- oestrogen
- progesterone.
What name is given to things like condoms, the birth control pill and IUDs which are meant to prevent pregnancy?
Contraceptives
In what form are oral contraceptives given?
form of pills or tablets. They are placed in the mouth and swallowed.
The first birth control pills contained large amounts of what hormone?
high levels of the hormone oestrogen to prevent ovulation
Due to side effects the pill now contains lower doses of oestrogen.
What does IVF stand for?
In Vitro Fertilisation
disadvantages of IVF (6)
- the success rate is not very high
- it is emotionally very stressful for both parents
- it’s physically demanding on the mother
- can lead to multiple births (triplets, twins etc.) which is very risky for both the baby and mother.
- expensive - could be used for other things like treatment for cancer
- not all embryos that are created enters the mother causing them to be destroyed - people find this unethical
Two hormones are responsible for the thickening of the uterus during the menstrual cycle. what are they?
Oestrogen and progesterone
Ovulation occurs approximately every how many days?
approximately every 28 days
Name the organ where oestrogen is made.
woman’s ovaries
Oestrogen stops or slows the production of what hormone? and why
FSH (Follicle Stimulating Hormone)
to ensures that only one egg is released per cycle, which is necessary for a successful fertilization and pregnancy.
The lining of the uterus will be shed if the egg released at ovulation is not what?
fertilised
what will happen when an ovum implants?
the thickened uterine lining. This initiates the beginning of pregnancy.
what hormones might an oral contraceptive contain?
oestrogen and progesterone
what’s an embryo?
an early stage of development after a fertilized egg
Which hormone is responsible for the development of secondary sexual characteristics in girls during puberty?
oestrogen
Which hormone is responsible for the development of secondary sexual characteristics in boys during puberty?
testosterone
Name a mechanical method of birth control.
condoms
The process of development of secondary sexual characteristics that teenagers go through is called what?
puberty
Condoms are an example of which type of contraception?
Condoms are a form of mechanical or barrier contraception
A vasectomy is an example of which method of contraception?
surgical method
After an egg is released, the empty follicle in the ovary secretes __________, which inhibits both FSH and LH. What word completes the sentence?
progesterone
Which hormone is primarily responsible for stimulating ovulation?
Luteinizing Hormone (LH)
