The Endocrine System

Question 1

Outline the endocrine system

Answer 1

• A series of glands in the body that manufacture and secrete hormones
• Its function is to communicate chemically throughout the body
• Hormones send messages to target organs of the body by travelling in the bloodstream

Question 2

Describe hormones and how they work

Answer 2

• Chemicals that circulate in the bloodstream and are carried to target sites in the body
• A hormone affects target cells that have the receptors of that hormone
• When enough receptor sites are stimulated, a physiological reaction in the target cell is produced.
• Too little or too much at the wrong time can result in dysfunction of bodily system

Question 3

Describe the pineal gland

Answer 3

• Releases melatonin
• Responsible for important biological rhythms e.g. sleep-wake cycle

Question 4

Describe the pituitary gland

Answer 4

• Known as the ‘master gland’
• Produces hormones that influence the release of hormones from other glands

Question 5

Describe the hypothalamus

Answer 5

• Just above the pituitary gland
• Stimulates and controls release of hormones from pituitary gland
• Receives information from other sources about the basic functions, then uses it to regulate these functions (controlling pituitary)

Question 6

What is negative feedback?

Answer 6

High levels of hormones produced in other endocrine glands can stop the hypothalamus and pituitary releasing more of their own hormones, prevents hormones levels from rising too high

Question 7

Describe the thyroid gland

Answer 7

• Releases thyroxine
• Responsible for regulating metabolism

Question 8

What are the two parts of the pituitary gland?

Answer 8

• Anterior pituitary gland (front)
• Posterior pituitary gland (back)

Question 9

Describe the anterior pituitary gland

Answer 9

• Releases ACTH (stimulates the adrenal gland to produce cortisol) as a response to stress
• Produces luteinising hormone (LH) and follicle-stimulating hormone (FSH) that are important in the control of reproductive functioning and sexual characteristics

Question 10

Describe the posterior pituitary gland

Answer 10

Releases oxytocin, which stimulates contraction of the uterus during childbirth and it’s important for mother-infant bonding

Question 11

Where are the adrenal glands located?

Answer 11

They sit on top of the kidneys

Question 12

What are the two parts of the adrenal glands

Answer 12

• Outer part of the glands: adrenal cortex
• Inner part of the glands: adrenal medulla

Question 13

What is the main distinction between the two parts of the adrenal glands?

Answer 13

Hormones released by adrenal cortex are necessary while those released by the adrenal medulla aren’t

Question 14

Describe the adrenal cortex

Answer 14

• Produces cortisol, which regulates/supports a variety of bodily functions. Productions is increases in response to stress
• If cortisol levels is low, there’s low blood pressure, poor immune function and inability to deal with stress
• Produces aldosterone, responsible for maintain blood volume and pressure

Question 15

Describe the adrenal medulla

Answer 15

• Releases adrenaline and noradrenaline, hormones that prepare the body for fight or flight.
• Adrenaline helps the body respond to stressful situations (increasing heart rate and blood flow to muscles and brain, and helping with the conversion of glycogen to glucose to provide energy.
• Noradrenaline constricts the blood vessels, causing blood pressure to increase

Question 16

Describe the ovaries as part of the endocrine system (female)

Answer 16

• Responsible for the production of eggs, hormones oestrogen and progesterone.
• Progesterone is more important in the post-ovulations phase of the menstrual cycle and is associated with heightened sensitivity to social cues.

Question 17

Describe the testes as part of the endocrine system (male)

Answer 17

• Produces testosterone, causes development of male characteristics like facial hair, deepening of voice and growth spurts during puberty.
• Testosterone production is controlled by hypothalamus and pituitary.