Bio paper 2

Homeostasis

the process of keeping the internal conditions of the body constant

Receptors

cells found in sense organs, e.g. eyes, ears, nose

Effectors

part of the body (e.g. a muscle or a gland) that produces a response to stimuli

Negative feedback

a set of events that detects a variable and then corrects any change in the variable away from a set value

Thermoregulatory centre

the part of the brain responsible for maintaining a constant body temperature in warm-blooded animals

Vasodilation

occurs when blood vessels in the skin become wider so that more blood flows close to the surface of the skin to increase heat loss

Vasoconstriction

occurs when blood vessels in the skin become narrower so that less blood flows close to the surface of the skin

Central nervous system (CNS)

the part of the nervous system made up of the brain and spinal cord

Synapse

the gap between two neurones

Cerebral cortex

the area at the top of the brain that is responsible for intelligence and initiating movements

Cerebellum

part of the brain, at the rear, that is responsible for balance and controlling movements

Medulla

the area of the brain that controls heartbeat and breathing

Retina

the layer at the back of the eye that contains the lightsensitive receptors

Optic nerve

a collection of neurones that pass nerve impulses from the eye to the brain

Sclera

the tough white coating to the eye

Cornea

the transparent membrane that covers the eyeball

Iris

the coloured part of the eye that changes the size of the pupil in response to different light intensities

Pupil

the opening at the front of the eye that lets light enter

Ciliary muscles

muscles in the eyes that can change the shape of the lens for accommodation

Suspensory ligaments

structures that attach the ciliary muscle to the lens in the eye

Accomodation

process that occurs to enable the eye to change so that objects at different distances can be focused on the retina

Refract

to bend / change the direction of a light ray (commonly performed by a lens)

Myopia

the condition that stops a person’s eyes from focusing on distant objects clearly

Hyperopia

the condition that stops a person’s eyes from focusing on near objects clearly

Endocrine system

a system of glands that release hormones directly into the bloodstream

Hormone

a chemical messenger produced by a gland that travels in the blood to its target organ

Pituitary gland

a small gland at the base of the brain that produces hormones; known as the ‘master gland’

Adrenaline

hormone released from the adrenal gland, which prepares the body for ‘fight or flight’

Thyroxine

a hormone released from the thyroid gland that controls the metabolic rate of the body

Type 1 diabetes

a condition where not enough insulin is produced by the pancreas

Type 2 diabetes

a condition where insulin is produced but the cells of the body do not respond to it

Urea

a waste product from the breakdown of proteins formed in the liver and excreted in urine

Deamination

the breakdown of excess amino acids in the liver

Selective reabsorption

the process of active transport that reabsorbs useful molecules back into the blood from the kidney tubules

Tubules

small tubes in the kidney, where blood is filtered, selective reabsorption takes place, and urine is produced

ADH

hormone released from the pituitary gland, which acts on the kidneys causing more water to be reabsorbed back into the blood

Dialysis

the artificial removal of urea and excess material from the blood (used when the kidneys fail)

Oestrogen

a hormone secreted by the ovaries that inhibits the production of FSH and triggers the production of LH

Ovulation

the release of an egg (ovum) from the ovary into the fallopian tube

Testosterone

a hormone produced by the testes that controls the male sexual characteristics

Menstrual cycle

the monthly cycle of an egg being released in females; controlled by hormones

Follicle stimulating hormone (FSH)

a hormone released by the pituitary gland that causes an egg to develop in the ovaries

Luteinising hormone (LH)

a hormone that stimulates the release of an egg in the menstrual cycle

Progesterone

a hormone that repairs the lining of the uterus after menstruation and prevents it breaking down

Contraception

mechanisms that are used to prevent pregnancy occurring as a result of sexual intercourse

Fertility drug

a drug that makes it more likely for sexual intercourse to result in pregnancy

In vitro fertilisation

a process in which an egg is fertilised by sperm outside of the body

Tropism

growth in response to a stimulus, e.g. plants growing towards the light

Gravitropic

describes a plant’s growth response to gravity (also called geotropic)

Phototropic

describes a plant’s growth response to light

Auxins

a group of growth hormones produced in plants

Gibberellins

a group of plant hormones

Ethene

a gas that acts as a plant hormone

Endocrine system

A system of glands that secrete hormones into the bloodstream.

Hormones

Chemical substances produced by glands that regulate various functions in the body.

Pituitary gland

Located in the brain; often referred to as the 'master gland' because it controls other glands and produces several hormones. controls growth in children, stimulates the thyroid gland to make thyroxine to control the rate of metabolism, in females – stimulates the ovaries to produce and release eggs, and make oestrogen, in males – stimulates the testes to make sperm and testosterone

Adrenaline

A hormone produced by adrenal glands that increases heart rate and prepares the body for 'fight or flight' response.

Thyroxine

A hormone produced by the thyroid gland that regulates metabolic rate and is important for growth.

Negative feedback

A process that helps to maintain balance by reversing changes in levels of substances in the body.

Pancreas

An organ that monitors and controls blood glucose levels by producing insulin and glucagon.

Type 1 diabetes

A form of diabetes where the pancreas produces insufficient insulin.

Type 2 diabetes

A form of diabetes where body cells do not respond to insulin; often associated with obesity.

Insulin

A hormone produced by the pancreas that lowers blood glucose levels.

Glucagon

A hormone produced by the pancreas that raises blood glucose levels.

FSH (Follicle Stimulating Hormone)

A hormone that stimulates the maturation of eggs in the ovaries.

LH (Luteinising Hormone)

A hormone that stimulates the release of a mature egg from the ovaries.

Oestrogen

The main female reproductive hormone, produced in the ovaries, which regulates the menstrual cycle.

Progesterone

A hormone that maintains the thick lining of the uterus.

Testes

The male reproductive glands that produce testosterone and sperm. controls development of male secondary sexual characteristics, involved in sperm production and maturation.

Ovaries

The female reproductive glands that produce oestrogen and eggs. controls the development of female secondary sexual characteristics and controls the mentral cycles

Menstrual cycle

A monthly cycle regulated by hormones that prepares the female body for potential pregnancy.

IVF (In Vitro Fertilisation)

A medical procedure in which fertilisation occurs outside the body to treat infertility.

Contraception

Methods used to prevent pregnancy during sexual intercourse.

Phototropism

The growth of plant shoots towards light, controlled by the hormone auxin.

Gravitropism

The growth of plant roots towards gravity, also influenced by auxin levels.

Auxin

A plant hormone that regulates growth by directing the development of shoots and roots.

Diabetes

A non-communicable disease characterized by uncontrolled blood glucose levels due to insulin issues.

Human development

The series of changes in the human body during growth, influenced by hormonal actions.

Gland

An organ that produces and secretes hormones for specific functions in the body.

Hormonal regulation

The process by which hormones control various functions and processes in the body.

Basal metabolic rate

The rate at which the body uses energy while at rest, influenced by thyroxine.

Stress response

The physiological reaction to a perceived threat, primarily mediated by adrenaline.

Secondary sexual characteristics

Physical traits that develop during puberty, influenced by sex hormones.

Fertility treatment

Medical procedures to address infertility, including hormonal treatments.

Spermicidal agents

Substances that kill or incapacitate sperm to prevent pregnancy.

Abstinence

Choosing not to engage in sexual intercourse as a method of contraception.

Sterilisation

Surgical methods employed to permanently prevent pregnancy.

Copper IUD

A non-hormonal intrauterine device that prevents fertilization by inhibiting sperm.

Luteal phase

The phase in the menstrual cycle after ovulation when the corpus luteum forms.

FSH control

Regulated by hormonal feedback mechanisms to manage egg maturation in females.

Thyroid role

controls the rate of metabolism in the body

Pancreas

controls blood glucose levels

Adrenal role

prepares the body for stress, involved in the ‘fight or flight’ response

How do the effects of the endocrine system compare to those of the nervous system?

endocrine system effects are slower but act for longer compared to the rapid, short-lived effects of the nervous system.

Where is the pituitary gland located?

brain

Which organ monitors and controls blood glucose concentration?

pancreas

Which hormones interact to regulate blood glucose levels?

insulin and glucagon

What is the cause of Type 1 diabetes?

pancreas produces insufficient insulin due to autoimmune destruction of insulin-producing beta cells.

What is the cause of Type 2 diabetes?

body cells no longer respond to insulin or the pancreas does not produce enough insulin.

What is the function of FSH?

causes eggs to mature in the ovaries, and stimulates ovaries to produce oestrogen