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 GCSE OCR GATEWAY Biology Complete Revision Summary

HORMONAL CONTROL

• Human endocrine system

• Negative feedback systems in hormonal control – Higher

• Thyroxine and adrenaline – Higher

• Hormones and puberty

• The menstrual cycle

• Hormonal methods of contraception

• Non-hormonal methods of contraception

• Hormones used in reproductive technology to treat infertility – Higher

• Evaluating infertility treatments – Higher

HORMONAL and NERVOUS SYSTEM

Hormones

• They are chemical messenger secreted by the endocrine glands
• they are secreted in the blood and travel to the target organ
• Target organ has receptors and hormones
• bind to the receptor and triggers a response
• It produces a slower but long term response

Nervous System

• Is the system of neurones which send electrical impulses to produce a response
• The message is transmitted via electrical impulses
• The response produced is localised and impulses do not travel large distances
• It produces quick but short term response

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PITUITARY : THE MASTER GLAND – Smallest endocrine gland of the body. It is pea shaped, ovoid, reddish brown gland situated at base of the brain in cavity, sella turcica of sphenoid bone. It controls almost all endocrine glands. Hence it is also called master gland

• Master Gland
• It controls other glands of the body
• Follicle Stimulating Hormone
• Antidiuretic Hormone
• Thyroid Stimulating Hormones

EXAMPLES

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_The endocrine system__

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CONTROL OF BLOOD GLUCOSE

• Pancreas Insulin and Glucagon (lowers the blood glucose level)
• Increases the blood glucose level)
• Insulin Effect
• It increases the permeability of cells to glucose
• It converts excess glucose to -glycogen
• It converts excess glucose to fats
• It stops the breakdown of fats

Glucagon 'is the hormone

Glycogen is the stored carbohydrate

DIABETES

DIABETES TREATMENT

TYPE 1

• Insulin injections directly into the blood stream.
• Less taken orally as being a protein hormone it can get digested by stomach.
• The insulin converts excess glucose into glycogen and control the blood glucose level.
• Less intake of carbohydrates.
• Pancreatic Transplant
• Pancreatic Cell Transplant
• Using stem cells to regenerate pancreatic cells.

TYPE 2

• Balanced diet
• Regular Exercise
• Weight Management
• Drug to increase sensitivity of pancreas to insulin
• Insulin injections to increase the concentration of insulin to make them more responsive to insulin.

NEGATIVE FEEDBACK

• When the level of anything rises above optimum like glucose concentration, water concentration or temperature negative feedback decreases it
• When the level of anything decreases below optimum the negative feedback raises it.

FIGHT OR FLIGHT HORMONE

• Stress Hormone
• Increase heart rate
• Increase breathing rate
• Dilate the pupil

Emergency Hormones

• Increase Blood Flow
• Increase the flow of oxygen to the brain
• Divert blood flow away from the gut

 HUMAN REPRODUCTIVE SYSTEM

TESTOSTERONE

Male hormone responsible for secondary sexual characters

OESTROGEN

Female hormone responsible for secondary sexual characters

MENSTURATION CYCLE

 HORMONES OF MENSTURATION

CONTRACEPTION METHODS

Preventing Sperms to reach the egg. Preventing the implantation of the zygote in the uterus.

Barrier Methods: Prevent the sperm to meet the eggs

Hormonal Methods: Prevents the eggs to mature or prevent the implantation of eggs in the uterus.

Chemical Methods: Kills the sperm

Intrauterine Device: Prevent embryo from implanting

Surgical Method: It is permanent contraception

HOW CONTRACEPTION WORKS?

Contraceptive Pills

• They contain the mix of female hormones oestrogen and progesterone. -MIX PILL
• Prevent the release of FSH preventing the maturation of eggs
• Make thick mucus in the cervix to prevent the entry of sperms.
• Prevent the uterus linning development, preventing implantation.
• Some pills are progesterone only pills.
• A contraceptive implant is also inserted which slowly release progesterone in the uterus.
• A contraceptive patch also absorbs the mix of hormones into the blood
• Side Effects: blood pressure, has to be taken daily changes in menstural pattern

Contraceptive Pills

• They contain the mix of female hormones oestrogen and progesterone. -MIX PILL
• Prevent the release of FSH preventing the maturation of eggs
• Make thick mucus in the cervix to prevent the entry of sperms.
• Prevent the uterus linning development, preventing implantation.
• Some pills are progesterone only pills.
• A contraceptive implant is also inserted which slowly release progesterone in the uterus.
• A contraceptive patch also absorbs the mix of hormones into the blood
• Side Effects: blood pressure, has to be taken daily changes in menstural pattern

Intra Uterine Device

• Copper T is inserted into the uterus
• It releases copper ions which are toxic to sperms
• The device also prevent the implanting of the embryo into the uterus
• Some releases progesterones which works the same like contraceptive pills
• Prevent the release of FSH preventing the maturation of eggs
• Make thick mucus in the cervix to prevent the entry of sperms.
• Prevent the uterus linning development, preventing implantatiom
• Side Effects: Infection; Internal Bleeding

 Surgical Methods

VASECTOMY: Male Sterlization

• Sperms ducts are cut and sealed so that the sperms cannot enter the urethra preventing fertilization.

TUBECTOMY: Femal Sterlization

• The oviducts are cut and tied to prevent the release of egg which prevent
• Sterlizatlom
• Side Effects - It is permanent.

INFERTILITY PROBLEMS

OVULATION PROBLEM

• The eggs do not mature or problem ovulating.
• The women is given fertility drugs which are the mix of FSH and LH that stimulated maturation and ovulation

FAULTY TUBES

IMPLANTATION

• In Vitro Fertilization where fertilization is performed in the laboratory and the embryo is implanted back in the uterus for the development

PREGNANCY DEVELOPMENT

• Surrogate Mother where the fertilized egg is implanted into another mother who gives birth

IN VITRO FERTILIZATION

• Expensive
• Results in multiple embryos
• Premature births
• Birth with disability
• Not always successful

Fertility drugs to stimulate ovulation

Ovary and sperm are collected to perform fertilization.

Fertilized egg is developed in the laboratory giving suitable conditions to develop into an embryo.

Embryo is inserted into the uterus

Develops into a baby.

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References:

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Make sure you have watched the above videos and are familiar with the key definitions before trying these questions. It is also good to time yourself while doing these questions so that you can work on the speed as well

Human Nervous System

• Human Nervous System 1 MS
• Human Nervous System 1 QP
• Human Nervous System 2 MS
• Human Nervous System 2 QP
• Human Nervous System 3 MS
• Human Nervous System 3 QP

Hormonal Coordination In Humans