The endocrine system

Question 1

Name three important roles of the endocrine system

Answer 1

1. regulates mood
2. growth and development
3. tissue function
4. metabolism
5. sexual function and reproduction
6. regulate the action of smooth and cardiac muscle

Question 2

In short the role of the endocrine system can generally be described as maintaining

Answer 2

homeostasis

Question 3

What does the endocrine system consist of? (3)

Answer 3

1. glands
2. hormones
3. receptor cells of the body.

Question 4

What do the glands do?

Answer 4

Glands are specialised organs that release hormones.

Question 5

What are hormones?

Answer 5

These are chemical messengers that travel through the blood to target specific cells and control the activity of the various organs and functions of the body.

Question 6

The increase in your heart rate that occurs when you exercise or are very stressed results from increased stimulation by the nervous system and the release of the hormones … known as the what?

Answer 6

catecholamines

Question 7

What are catecholamines and what glands are they released from?

Answer 7

These are released from the adrenal glands and target special receptor cells in the heart and so increase the rate and force of its contraction.

Question 8

When an endocrine gland is stimulated, it releases hormones to where?

Answer 8

into the blood

Question 9

How often can hormones fluctuate?

Answer 9

they can fluctuate over longer periods of time, resulting in daily and monthly cycles, such as the menstrual cycle.

Question 10

Your body has several regulatory mechanisms to ensure it releases appropriate levels of hormones over time. These include signals from the nervous system and chemical changes in the blood. Your body regulates most hormone secretion by a system called what?

Answer 10

negative feedback system

Question 11

what is the negative feedback system?

Answer 11

the secretion of a hormone results in some physiological change in the body, which in turn inhibits further hormone secretion.

Question 12

Give a metaphoric example for the negative feedback system to help understand this

Answer 12

how a thermostat in a heating system controls room temperature. When the room temperature falls below a certain level, the thermostat signals the boiler to produce heat. Once the room temperature rises to the preset level, the thermostat’s signal stops, and the boiler stops producing heat. If the room temperature drops below the preset level, the cycle begins again.

Question 13

Where is the Hypothalamus?

Answer 13

hypothalamus is a small cone shaped gland in the brain

Question 14

What does the Hypothalamus do?

Answer 14

links the nervous system to the endocrine system

Question 15

What is the main role of the Hypothalamus?

Answer 15

to maintain the body’s internal balance, which is known as homeostasis.

Question 16

How is the hypothalamus alerted and what does it do next?

Answer 16

The hypothalamus is alerted to any imbalances that need attention.

it will respond by releasing hormones that will act on the pituitary gland, which in turn will release hormones that regulate other endocrine glands and organs.

Question 17

Name some secondary functions of the hypothalamus (5)

Answer 17

1. regulating temperature
2. hunger
3. blood pressure
4. digestion
5. circadian rhythms by acting on the pituitary gland

Question 18

Where is the pituitary gland located?

Answer 18

The pituitary gland is a small gland, approximately the size of a marble, at the base of the brain.

Question 19

What is the pituitary gland controlled by?

Answer 19

It is controlled by the nervous system and hormones from the hypothalamus.

Question 20

The pituitary gland consists of three parts or lobes:

Answer 20

anterior, intermediate, and posterior.

Question 21

What hormones does the posterior lobe of the pituitary gland secrete and what do these do?

Answer 21

The posterior lobe of the pituitary gland secretes two hormones: oxytocin and antidiuretic hormone (ADH).

ADH promotes water conservation reducing the risk of dehydration during periods of heavy sweating.

Question 22

What hormones does the anterior lobe of the pituitary gland secrete and what do these do?

Answer 22

The anterior lobe secretes six hormones, three of which are particularly relevant to exercise.

These include thyrotropin or thyroid-stimulating hormone (TSH), which controls the amount of thyroxin and triiodothyronine hormone produced and released by the thyroid gland, adrenocorticotropic hormone (ACTH)

which controls the secretion of hormones from the adrenal cortex and growth hormone.

Question 23

Where is the HGH growth hormone secreted from in the pituitary gland and what does this do?

Answer 23

Human growth hormone (HGH), or somatotropin, is secreted by the anterior pituitary gland.

It targets a variety of tissues in the body including bone, skeletal muscle, fat cells, liver tissue and immune cells. Human growth hormone increases the growth rate of the skeleton and skeletal muscles during childhood and adolescence. In adults, human growth hormone maintains bone mass and healing of injuries.

Question 24

In relation to exercise why do we need this growth hormone? (2)

Answer 24

1. it promotes muscle growth by facilitating amino acids into cells and increasing protein synthesis.
2. It optimises fuel during exercise by stimulating fats for energy while decreasing the use of glucose, so less is used by the cells. This glucose-sparing action helps maintain blood glucose levels and contributes to sustaining prolonged exercise.

Question 25

What two glands does the thyroid gland secrete?

Answer 25

Triiodothyronine (T3) and thyroxine (T4)

Question 26

What do the two hormones secreted by the thyroid gland do?

Answer 26

regulation of:
1. oxygen use
2. basal metabolic rate
3. cellular metabolism
4. growth and development.

The thyroid hormones increase the metabolic rate of the body by stimulating the use of cellular oxygen to produce ATP. They also stimulate the synthesis of additional sodium–potassium pumps, which then use more ATP.

Question 27

As cells produce and use more ATP, more heat is given off, and body temperature rises. This is known as the ______ effect of the thyroid hormones.

Answer 27

calorigenic effect

Question 28

What is the major role played by the calorigenic effect?

Answer 28

This phenomenon plays a major role in the maintenance of normal body temperature, particularly in very cold temperatures.

Question 29

The effect of the thyroid hormones on metabolism is considerable, as they have been shown to increase the metabolism of the body by 60–100%. Conversely insufficient levels have been shown to result in decrease in metabolism of 30–50%.

Answer 29

60–100% - 30–50% - In the regulation of metabolism, the thyroid hormones stimulate protein synthesis and increase the use of glucose and fatty acids for ATP production.

Question 30

Name the outer part of the adrenal gland

Answer 30

the adrenal cortex

Question 31

Name the inner part of the adrenal gland

Answer 31

the adrenal medulla

Question 32

The adrenal cortex secretes over thirty hormones, known as what?

Answer 32

corticosteroids.

Question 33

The corticosteroids are placed into three major groupings: mineralocorticoids, glucocorticoids and gonadocorticoids. What do the first 2 do?

Answer 33

The mineralocorticoids play a valuable role by maintaining electrolyte balance in the extracellular fluids, such as plasma.

The glucocorticoids help regulate metabolism and resistance to stress.

Question 34

What do hormones are secreted by the adrenal medulla?

Answer 34

The adrenal medulla secretes two hormones: epinephrine and norepinephrine, known as adrenaline and noradrenaline. These hormones are the catecholamines.

Question 35

When does the adrenal medulla secrete it’s hormones?

Answer 35

In stressful situations and during exercise, the adrenal medulla releases the catecholamines. These produce powerful effects and contribute to the fight or flight mechanism.

Question 36

The catecholamines work together to produce the following effects to help our bodies to exercise and respond to stress: (3)

Answer 36

1. increased rate and force of heart contraction, blood pressure, metabolic rate, breakdown of glycogen to glucose (glycogenolysis) in the liver and muscle
2. The increased release of glucose and free fatty acids into the blood; the redistribution of blood to the skeletal muscles and heart away from the abdominal area
3. The increased dilation of the airways and the increased respiratory rate and depth

Question 37

Many of the effects caused by the adrenal glands may occur prior to exercise – this is known as the what? what does it do and give an example!

Answer 37

anticipatory response

which is the body’s way of preparing for exercise.

For example, a client’s pre-exercise resting heart rate usually increases well above its normal resting value.