Organism Level Systems (GCSE OCR)

ADH

ADH

A hormone secreted by the pituitary gland that increases water reabsorption in the kidney.

Adrenaline

A hormone released by the adrenal gland that increases heart rate and breathing rate.

Auxin

A plant hormone responsible for cell elongation.

Central Nervous System (CNS)

Comprising the brain and spinal cord.

Cerebellum

Brain region controlling unconscious functions like posture and balance.

Cerebral Cortex

Outer layer of the cerebrum.

Cerebrum

Brain region responsible for voluntary actions and divided into hemispheres.

Ciliary Body

Part of the eye containing the ciliary muscle for focusing.

Color Blindness

Condition with defects in retina receptors.

Colorception

Methods for preventing pregnancy.

Cornea

Eye part refracting light onto the retina.

Dormancy

Period when seeds hibernate.

Effector

Gland or muscle producing a response to stimuli.

Endocrine Glands

Cells secreting hormones into the bloodstream.

Endocrine System

System releasing hormones to control metabolism and growth.

Ethane

Plant hormone promoting fruit ripening.

Follicle Stimulating Hormone (FSH)

Female hormone for egg maturation.

Geotropism

Plant growth response to gravity.

Germination

Process of seeds developing into plants.

Gibberellins

Plant hormones initiating germination and flowering.

Estrogen Decrease

Reduction in estrogen levels leads to an increase in LH and FSH.

Ovulation

The release of an egg from the ovary occurs when LH and FSH levels peak.

Progesterone

Hormone that maintains the thick lining of the uterus and inhibits the release of LH and FSH.

Menopause

The cessation of the menstrual cycle, typically occurring around 50-55 years of age in women.

Oral Contraceptives

Birth control pills containing progesterone and estrogen that inhibit FSH production to prevent egg maturation.

Contraceptive Implants

Devices releasing progesterone slowly to prevent egg release and thicken cervical mucus.

Auxin

Plant hormone responsible for positive phototropism and negative gravitropism in shoots and roots.

Gibberellins

Plant hormone crucial for seed germination, flowering, and leaf shedding.

Ethane

Plant hormone involved in cell division and fruit ripening, used in the food industry.

Homeostasis

Maintenance of a stable internal environment despite external changes, crucial for enzyme function.

Insulin

Hormone produced by the pancreas to lower blood glucose levels by promoting glucose uptake and storage.

Glucagon

Hormone released by the pancreas to raise blood glucose levels by breaking down glycogen.

Diabetes

Disease characterized by improper blood sugar control, with Type 1 and Type 2 variations.

Kidneys

Organs vital for filtering waste from the blood, regulating water balance, and maintaining body substances.

ADH

Antidiuretic hormone that controls water loss in urine by increasing water reabsorption in the kidney tubules.