Week 5 - endocrine system

Question 1

Paracrine signal

Answer 1

If a cell sends a signal, and the signal is received by a cell nearby

Question 2

Autocrine signal

Answer 2

If a cell sends a singal and that signal creates a response from the same cell

Question 3

Where can cell signalling occur via synapses?

Answer 3

In the nervous system, where neurotransmitters are released from a nerve ending and diffuse to receptors in very close proximity

Question 4

2 types of glands in the body

Answer 4

Exocrine glands - secrete their products e.g. sweat (exit the body) or enter the lumen of another organ e.g. intestines
Endocrine glands - ductless glands and release hormones straight into the blood

Question 5

Endocrine system key information

Answer 5

One of the bodies two main communication systems
It consists of glands and organs that secrete hormones
A single gland may secrete multiple hormones
Hormones are chemical messengers carried to the blood by target cells

Question 6

What are hormones

Answer 6

They are chemical messengers that travel in blood to target cells

Question 7

Functions of hormones

Answer 7

They help regulate metabolism and contraction of smooth and cardiac muscle fibres
They control growth and development
They regulate the operation of the reproductive system
They help establish the circadian rhythm

Question 8

Differences between the endocrine and nervous system

Answer 8

Endocrine - acts more slowly and often longer lasting effects
Nervous system - instantaneous and responses are short lived

Question 9

3 main structural classes of hormones

Answer 9

Amines e.g. thyroid, catecholamines
Peptides and proteins e.g. insulin
Steroids

Question 10

How do peptide and catecholamine hormones travel?

Answer 10

They are water soluble and when they are released from the endocrine gland, they dissolve in the blood stream, meaning they move easily around the blood

Question 11

How do steroids and thyroid hormones travel?

Answer 11

They bind to plasma proteins to travel through the circulatory system

Question 12

Brief summary of how a hormone gets from the endocrine system to excretion

Answer 12

Endocrine cell secretes hormone
Travels to blood (either dissolves in blood or binds to plasma protein)
Gets to target cell
Extracted in urine/faeces
Inactivated by metabolism

Question 13

What is hormone secretion controlled by

Answer 13

1. Plasma concentration of an ion or nutrient that the hormone regulates
2. Neural input to the endocrine cells
3. Other hormones

Question 14

1. Plasma concentration of an ion or nutrient that the hormone regulates

Answer 14

1. After a meal, digestion of food results in glucose absorbing into blood, causing an increase in plasma glucose concentration. Stimulates insulin secretion cells to release more insulin. Insulin is released from endocrine cells into blood, travels around body to hit target cells for insulin. Once the target cells hit the receptors on organs and tissues, this increases the action of insulin to take glucose out of blood and into those cells for storage. Example of negative feedback loop

Question 15

2. Neural input to the endocrine cells

Answer 15

2. The autonomic nervous system controls hormone secretion via the adrenal medulla and other endocrine glands. Neurones in the hypothalamus also secrete hormones. Neural input from the autonomic nervous system controls the secretion of many hormones.

Question 16

Other hormones

Answer 16

3. Often the secretion of a particular hormone is directly controlled by the blood concentration of another hormone. A hormone that stimulates the secretion of another hormone is often referred to as tropic hormone e.g. Thyroid-stimulating hormone (TSH) or Follicle stimulating hormone (FSH)

Question 17

The responsiveness of a target cell to a hormone depends on

Answer 17

-the hormones concentration in the blood
-the abundance of the target cells hormone receptors
-influences exerted by other hormones