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Question 1

Hypothalamus to anterior pituitary

Answer 1

Hypothalamic neurons release chemicals ( hormones ) into a blood portal connection to anterior pituitary gland cells

Question 2

Hypothalamus to posterior pituitary

Answer 2

Hypothalamic neurons have long axons that extend into and terminate ( axon thermals ) in the posterior pituitary gland

Question 3

The posterior pituitary gland: Where is the hypothalamus connected and explain in depth the posterior pituitary hormones

Answer 3

The hypothalamus is connected to the posterior pituitary by neurons
- cell bodies in the hypothalamus
- axon terminate in the posterior pituitary gland

Posterior pituitary hormones
- are made in hypothalamic neuron cell bodies
- travel down the axon to be stored in the axon terminal until required
- and then are released into the main bloodstream when an action potential depolarises the axon terminal

Question 4

The posterior pituitary hormones

Answer 4

There are 2 types: Oxytocin and Anti-Diuretic hormone ( ADH )

Question 5

What is Oxytocin

Answer 5

This is one of the posterior pituitary hormones
- water soluble
- stimulates milk release during breastfeeding an infant
- stimulated the contraction of uterine muscles during childbirth

Question 6

What is Anti-Dluretic Hormone ( ADH )

Answer 6

• water soluble
• stimulates the kidney to reabsorb water when a person is dehydrated
• one of the hormones secreted during exercise and stress response

Question 7

What is the posterior pituitary hormone initiated by

Answer 7

Baby sucking or dehydration

Question 8

What stimulus is the anterior pituitary gland

Answer 8

Exercise
Puberty
Stress

Question 9

The Anterior pituitary gland, where is the hypothalamus connect to

Answer 9

It’s connected to the anterior pituitary by a portal blood stream
- hypothalamic neurons secrete “releasing” or “inhibiting” hormones
-they travel via a blood portal system to the anterior pituitary and binds to membrane receptors on anterior pituitary cells
- this causes the anterior pituitary cells to release an anterior pituitary hormone

Question 10

What are the 3 main anterior pituitary hormones

Answer 10

Growth hormone ( GH )
thyroid stimulating hormone ( TSH )
adrenocorticotropin hormone ( ACTH )

Question 11

Explain the growth hormone

Answer 11

• water soluble
• stimulates the liver, skeletal muscle and adipose for fuel mobilisation
• stimulates the liver to release IGF-1 for growth

Question 12

Explain the thyroid stimulating hormone (TSH)

Answer 12

• water soluble
• stimulates the thyroid gland to release thyroid hormones to increase basal metabolic rate

Question 13

Explain Adrenocorticortropin hormone ( ACTH )

Answer 13

• water soluble
• stimulates the adrenal gland ( cortex ) to release CORTISOL in a daily pattern and during the stress response

Question 14

What are the glands involved in cell metabolism

Answer 14

Hypothalamus
Pituitary Gland
Thyroid gland

Question 15

What is the general pattern of hormone release from hypothalamus

Answer 15

• Stimulus: this is external or internal, so excersize, stress or changes in environment ect
• hypothalamus: this is when it’s releasing or inhibiting hormones, releasing hormones stimulate the anterior pituitary gland while inhibiting hormones suppress its activity
• anterior pituitary gland: Releasing hormones from the hypothalamus bind to receptors on anterior pituitary cells, prompting the release of specific pituitary hormones. These hormones then enter the bloodstream.
• target endocrine organ: The pituitary hormones travel to target endocrine organs, such as the thyroid gland, adrenal cortex, or gonads.
  Upon stimulation by pituitary hormones, target endocrine organs release their hormones, often referred to as the “3rd hormone.”
• target effectors - The hormones released by the target endocrine organs act on various effectors, such as tissues or organs, to exert their physiological effects.

Question 16

Hypothalamic pituitary- thyroid axis

Answer 16

This is the process that stops when excersize stops or cold stress if removed

• stimulus- excersize and cold stress
• hypothalamus secretes - In response to the stimulus, the hypothalamus secretes Thyrotropin-Releasing Hormone (TRH).
• anterior pituitary gland - TRH stimulates the anterior pituitary gland to release Thyroid-Stimulating Hormone (TSH).
• thyroid gland secretes - TSH stimulates the thyroid gland to secrete thyroid hormones, primarily triiodothyronine (T3) and thyroxine (T4).
• target of thyroid hormone: all body cells - Thyroid hormones act on all body cells. Their effects include:
• Increasing the basal metabolic rate, regulating energy production and consumption.
• Stimulation of growth in fetus and during early childhood.
• Increasing mental alertness.

Question 17

Thyroid gland location

Answer 17

• wraps around the trachea, just bellow the Adam’s apple
• on the anterior and lateral surfaces of the trachea

Question 18

Hormones of the thyroid gland

Answer 18

• thyroid hormones (T3 and T4) - made by cells that line the follicles, to increase metabolic activity, growth, alertness
• calcitonin - minor hormone involved in Ca2+ homeostasis

Question 19

Synthesis and storage and structure of thyroid hormones

Answer 19

T3 an pd T4

Structural and function units - thyroid follicles
Synthesis - thyroglobulin (TGB) is a protein made in thyroid follicles and contain tyrosine (Y) . Iodine enters cells lining and thyroid follicles and react with tyrosine ( Y ) in thyroglobulin (TGB)
= T3 = tyrosine with 3 iodine
= T4 = tyrosine with 4 iodine
Thyroid hormones ( T3 and T4 ) detach from iodised TGB as they are needed
- T3 and T4 travel in blood bound to a carrier protein

Question 20

What is iodine necessary for

Answer 20

Part of our diet as it is required for production of thyroid hormone

Question 21

Target cell activation by thyroid hormones ( T3 and T4 )

Answer 21

• they are made in advance and stored until required
• travels across the plasma membrane and it bounds to a carrier protein
• detaches from the carrier protein and enters the target cell
• thyroid hormone bind to the receptor in the nucleus
• specific genes are activated to transcribe messenger RNA ( mRNA )
• specific proteins are synthesised that lead to increased basal metabolic rate (BMR)
• response time: 45 minutes

Question 22

What is the Basal metabolic rate

Answer 22

The energy the body requires for its most basic functions to sustain life
-heart beating
-blood circulation
-respiration
-thermoregulation
-cell production
-nutrient processing
Your BMR influenced by your sex, age, body type and size, food intake, activity and exercise levels

Question 23

Effects of thyroid hormones on basal metabolic rate

Answer 23

Thyroid hormones increase the BMR by increasing
- thermogenesis ( body heat production)
- oxygen consumption and ATP production
- fat and protein breakdown

Thyroid hormone also have a complex unterstion with various organs to ensure that enough glucose is available for metabolic processes, without significantly disturbing plasma glucose homeostasis

Question 24

What are the glands involved in growth and cell metabolism

Answer 24

Hypothalamus
Pituitary Gland

Question 25

Patterns of growth hormone secretion. Daily secretion pattern

Answer 25

- growth hormone ( GH ) plasma concentration fluctuates over a day - GH concentration are the highest during sleep

Question 26

Pattern of GH secretion - lifetime secretion patterns

Answer 26

GH plasma concentration is higher in children than adults GH CONCENTRATION are highest during puberty and decline with age

Question 27

Growth hormone - direct and indirect effects

Answer 27

Direct effects - fuel mobilisation Muscle: inhabits cellular uptake of glucose stimulates protein synthesis Liver: stimulate glucose synthesis Adipose: increase fat breakdown The fuel is used by the cells for growth Indirect effects - for growth - via insulin like growth factor 1 (IGF 1 ) - IGF1 is realised from the liver cells when stimulated by GH - IGF- 1 promotes the growth of bones, muscle and other tissues

Question 28

Growth hormone and indirect effects

Answer 28

- IGF1 promotes the growth of bone, muscle and other tissues - cells must gather enough nutrients to divide and then rebuild all organelles and keep making ATP ect

Question 29

Hypothalamic - pituitary liver axis

Answer 29

The stimulus is excersize and sleep Hypothalamus Secretion - Releases Growth Hormone Releasing Hormone (GHRH) in response to exercise and sleep to stimulate the release of Growth Hormone (GH). - Releases Growth Hormone Inhibiting Hormone (GHIH) (also known as somatostatin) to inhibit the release of GH when needed. Anterior Pituitary Gland - Secretes Growth Hormone (GH) in response to GHRH stimulation. GH stimulates various tissues, including the liver, muscle, and fat. Liver, Muscle, and Fat Response - GH promotes fuel mobilization, encouraging the breakdown of glycogen and fat for energy during exercise. - The liver, in particular, responds by secreting **Insulin-like Growth Factor 1 (IGF-1) in response to GH stimulation. IGF-1 Effect - IGF-1 acts on all body cells, promoting cell growth and proliferation. - IGF-1 also provides negative feedback to the hypothalamus and anterior pituitary, reducing the release of GHRH and GH when its levels are elevated, thus regulating the axis. The process stops when exercise stops or when the individual wakes up, as the stimuli (exercise and sleep) cease. Negative feedback from IGF-1 reduces the release of GH and GHRH, helping to maintain homeostasis. All the mentioned hormones are water-soluble, meaning they can travel freely in the bloodstream to reach their target tissues and elicit their effects.