The endocrine system

Question 1

What is homeostasis?

Answer 1

the maintenance of a constant internal environment

Question 2

What mechanisms within the body allow homeostasis to occur?

Answer 2

-Body fluid- acts as an internal environment
-Skin-acts as a barrier
-Cells- are required to stay alive
-Lungs- keep O2 levels constant
-Kidneys-keep nitrogen waste constant (low)
-muscles- keep temperature constant (shivering)
-digestive system- helps keep nutrient levels constant

Question 3

What does the endocrine system do?

Answer 3

-sends hormones thru the circulatory system to control and coordinate body functions
-works with nervous system

Question 4

Name some of the functions that are controlled by the endocrine system?

Answer 4

metabolism, growth & development, sexual function & reproduction, heart rate, blood pressure, appetite, body temp

Question 5

What are the 12 parts of the endocrine system?

Answer 5

Hypothalamus, pineal gland, thyroid gland, thymus gland, heart, adrenal gland, stomach, kidney, pancreas, intestines, ovaries/testes

Question 6

Describe the role of the hypothalamus in the endocrine system?

Answer 6

• is a cluster of nerve cells that provides the main link between nerve cells and hormones.
  -It receives and processes signals from other brain regions and translates them into hormones. These hormones can then travel to pituitary gland

Question 7

Describe the role of the pituitary gland in the endocrine system?

Answer 7

located below hypothalamus.
-Produces hormones affecting growth and reproduction.
-Also controls function of other endocrine glands

Question 8

Describe the role of the pineal gland in the endocrine system?

Answer 8

• found in centre of brain-produces melatonin- helps body’s sleep schedule

Question 9

Describe the role of the Thyroid gland in the endocrine system?

Answer 9

located in front of neck below the larynx. Plays a role in metabolism including maintenance of body weight, rate of energy use, heart rate. Can store hormones

Question 10

Describe the role of the thymus gland in the endocrine system?

Answer 10

-produces 3 hormones that are involved in development of white blood cells
-produces progenitor cells which mature into T cells. These are then used to destroy cancerous cells.
-Located in upper part of chest

Question 11

Describe the role of the heart in the endocrine system?

Answer 11

• produces atriopeptin which reduces blood volume and pressure and helpts to regulate fluid balance

Question 12

Describe the role of the adrenal gland in the endocrine system?

Answer 12

• the outer layer manufactures steroid hormones that regulate metabolism of glucose, sodium and potassium. Also maintains fluid balance.
  -The inner layer produces adrenaline

Question 13

Describe the role of the stomach in the endocrine system?

Answer 13

• makes hormones that stimulate production or release of enzymes that aid digestion

Question 14

Describe the role of the kidney in the endocrine system?

Answer 14

• secretes erythropoietin which stimulates red blood cell production in bone marrow

Question 15

Describe the role of the pancreas in the endocrine system?

Answer 15

– contains clusters of cells (islets of Langerhan) which produce hormones insulin and glucagon which lower and raise blood glucose levels when required

Question 16

Describe the role of the intestines in the endocrine system?

Answer 16

makes hormones that stimulate production/ release of hormones that aid digestion

Question 17

Describe the role of the ovaries/testes in the endocrine system?

Answer 17

• produce female/male sex hormones, oestrogen and progesterone and testosterone

Question 18

What features within the body are required to communicate in order to carry out homeostasis?

Answer 18

between organelles, cells, tissues, organs and systems

Question 19

What are the 2 types of signals used within communication for homeostasis?

Answer 19

-Cell to cell communication of chemical messengers
-Transport of chemical messengers

Question 20

How does this communication occur?

Answer 20

-involves secretion of molecules (chemical messengers) by cells, into extracellular fluid
-Chemical messengers then travel to target cells
-Target cells contain receptors specific to the chemical messengers

Question 21

Name the types of chemical messengers?

Answer 21

-Paracrines
-autocrines
-neurotransmitters
-hormones
-cytokines

Question 22

What is the function of paracrine and how do they work?

Answer 22

-communicate with neighbouring cells in order to produce a response by . They are secreted into extracellular environment and reach their target by diffusion
-Requires a change in concentration gradient for a response to occur
-For a response to occur receiving cell must contain appropriate receptor

Question 23

What is the function of autocrines/ how do they work?

Answer 23

• the production and secretion of an extracellular mediator by a cell followed by the binding of the mediator to receptors on the same cell
  (the secretory cell is the target cell)
  -important within survival of pathological conditions eg.cancer
  -Is rare

Question 24

what is the function of neurotransmitters/ how do they work?

Answer 24

-are secreted by neurons from axon terminal across synapse by diffusion to a target cell
-receive and transmit electrochemical signals by neurotransmission
-Neuron is either excitatory or inhibitory depending on type of signal it releases
-signals are sent between pre and postsynaptic cells

Question 25

What is the function of hormones/ how do they work?

Answer 25

• are secreted from endocrine glands into extracellular fluid where they diffuse into the blood. The blood stream acts as a transport system to reach target cells

Question 26

What is the function of cytokines/ how do they work?

Answer 26

aid cell to cell communication in immune responses and act on a wide rang of targets-alert lymphocytes
-immune system depends on cytokine signalling to keep body functioning
-when a foreign particles are engulfed a cytokine signal is sent to lymphocytes. The signal is then recognised and lymphocytes are activated- helps maintain homeostasis

Question 27

What are the different methods of communication between cells?

Answer 27

-gap junctions
-contact-dependant
-local
-long distance

Question 28

What are the 4 types of hormones?

Answer 28

-peptide and protein hormones
-amino acids
-steroids
-eicosanoids

Question 29

what can hormones can be classified into?

Answer 29

-water or lipid soluble

Question 30

Describe how receptor response pathways work?

Answer 30

-Chemical messenger binds to receptor protein
-receptor protein activates intracellular signal molecules
-these molecules then alter target proteins
-this creates a response

Question 31

what are the key features of negative feedback?

Answer 31

-Helps maintain homeostasis
4 key features:
-System variable (characteristic that needs to be regulated)
-Set point (the ideal concentration of the system variable)
-detector (actual or current value of the system variable which needs to be assessed)
-correctional mechanism (reduce or elimate the difference between the actual value and ideal value)

Question 32

Describe the role/function of the hormone adrenaline?

Answer 32

-triggers fight/flight response
-causing increased heart and sweat rate, pupil dilation and blood vessel constriction in order to redirect blood towards major muscle groups, including heart and lungs
-Is a protein hormone and binds to complementary receptors outside of target cell to cause a response without entering the cell (is a first messenger)
-causes activation of an enzyme (second messenger) (Adenyl Cyclase)

Question 33

Describe the role/function of the hormone cortisol

Answer 33

• is a stress hormone
  -released from adrenal glands and secretion is controlled by hypothalamus, pituitary gland and adrenal glands
  -Response to cortisol release includes: increased blood sugar levels, heightened memory and attention, increased blood pressure, suppression of immune system, decrease serotonin and decreased sensitivity to pain