Ch. 2 Chemical Messengers

Question 1

Name the two systems that coordinate cells and how each does it

Answer 1

o NS: control by nerve impulses

o Endo: release of chemical messengers (hormones)

Question 2

Define Homeostasis

Answer 2

the maintenance of a relatively constant internal environment despite fluctuation in the external environment

Question 3

What are the two types of glands

Answer 3

Ex/Endocrine

Question 4

What is the difference between endocrine and exocrine glands

Answer 4

1. Exocrine gland- secretes to ducts > surface or cavity

Endocrine gland- secretes to extracellular fluid > capillaries > transported by blood.

Question 5

Why are endocrine referred to as ‘ductless’

Answer 5

released directly into blood

Question 6

Name 8 major endocrine glands

Answer 6

1. Hypothalamus
2. Pituitary
3. Thymus
4. Adrenal gland
5. Gonads (Ovaries and Testes)
6. Pineal gland
7. Thyroid gland/parathyroid
8. Pancreas

Question 7

Define hormone

Answer 7

a chemical secreted by an endocrine gland, and that affects functioning of a cell or organ

Question 8

What are the three ways hormones affect cells

Answer 8

1. Change shape of enzyme > changes rate of protein production
2. Rate of transcription/translation > protein production
3. Turn on/ off structural genes

Question 9

What are the three factors that effect functioning of hormones

Answer 9

1. Specific (lock and key): only influence cells with correct receptors
2. Saturation: has max rate when all receptors are occupied
3. Sensitivity: #/type of receptors on cells

Question 10

What are the (Three) types of hormones

Answer 10

Paracrine, Protein and Amine, Steroid

Question 11

Define paracrine and what are they also known as

Answer 11

>

any chemical secreted by a cell that diffuses to and affects adjacent cells

• Local hormones (affect only where produced)

Question 12

Name the three differences between paracrines and hormones

Answer 12

1. Target Cells
   P-All cells of organ
   H- Specialised cells
2. Transport
   P-Extracellular fluid/diffusion
   H-Bloodstream
3. Movement
   P-Remain in organ
   H-All around body

Question 13

Explain how Protein and Amine hormones work

Answer 13

• Bind to membrane as water soluble // can’t pass through
  1. Protein attach to receptor on membrane of target cell
  2. Hormone receptor complex
  3. Secondary Messenger diffuses through cell

Question 14

Explain how Steroid hormones work

Answer 14

• Insoluble // diffuse through phospholipid bilayer + bind to organelles

Question 15

What is enzyme amplification and what does it allow

Answer 15

• Small stimulus> large effect
  > EA: A series of chemical reactions in which the product of one step is an enzyme that produces an even greater number of product molecules at the next step

Question 16

What is hormone clearance and what are the two ways they are cleared

Answer 16

• Desired effect > turned off
  1. Broken down in target cell, or liver or kidney
  2. Excreted in bile or urine

Question 17

Define negative feedback

Answer 17

>

Negative feedback systems: a situation in which feedback brings about the opposite to, or reduces the effect of, the original stimulus

Question 18

What is releasing factors and inhibiting factors

Answer 18

o Releasing factors- stimulate release of hormone

o Inhibiting factors- slow down secretion of hormone

Question 19

How is the pituitary joined to the hypothalamus

Answer 19

infundibulum

Question 20

What are the two parts of the pituitary glands and what are their other names

Answer 20

Anterior (adenohyphsis)

Posterior (neurohypophsis)

Question 21

How are the anterior and posterior lobes connected to the hypothalamus each

Answer 21

Anterior= blood vessels (not nerves)

Posterior= nerves

Question 22

What are secretions of the anterior controlled by

Answer 22

releasing inhibiting factors

Question 23

What are the 6 hormones the anterior lobe releases

Answer 23

1. FSH
2. Luteinising hormone
3. Growth hormone
4. Thyroid stimulating hormone
5. Adrenocorticotropic hormone
6. prolactin

Question 24

Where is FSH released, its target organ and its effects

Answer 24

Anterior,

ovaries
testes

development of gamates

Question 25

Where is LH released, its target organ and its effects

Answer 25

Anterior Ovaries and testes O- ovulation T- secretion of testosterone

Question 26

Where is growth hormone released, its target organ and its effects

Answer 26

Anterior all cells growth and protein synthesis

Question 27

Where is thyroid stimulating hormone released, its target organ and its effects

Answer 27

Anterior thyroid gland secretion of hormones of thyroid

Question 28

Where is adrenocorticotropic released, its target organ and its effects

Answer 28

Anterior adrenal cortex secretions of hormones from AC

Question 29

Where is prolactin released, its target organ and its effects

Answer 29

Anterior Mammary glands milk production

Question 30

Why is posterior not a true gland

Answer 30

no hormones created only released

Question 31

How does the posterior work

Answer 31

o Hormones made in nerve cells in hypo > move down extensions through infundibulum to posterior > stored until release triggered by nerve impulses in hypo

Question 32

What are the two hormones released by the posterior

Answer 32

Antidiuretic hormone | Oxytocin

Question 33

Where is antidiuretic hormone released, its target organ and its effects

Answer 33

posterior kidneys reabsorption of water

Question 34

Where is oxytocin released, its target organ and its effects

Answer 34

posterior mammary glands (release milk) , uterus (contraction)

Question 35

What does the pineal gland secrete and what does the hormone do

Answer 35

- Secretes melatonin o Involved in regulation of sleep patterns o Stimulated by darkness, inhibited by light

Question 36

What is the main secretion of the thydroid gland, whats its target cell, and its main effects

Answer 36

Thyroxine most cells increase metabolic rate > heat production and oxygen consumption

Question 37

What does the parathyroid gland release, its target organ and main effects

Answer 37

parathyroid gland (parathormone) bones and kidney increase Ca level in blood

Question 38

What are the two disorders of the parathyroid

Answer 38

o Hyperparathyroidism: increase PTH secretion> bones soften and too much calcium= kidney stones o Hypoparathyroidism: too little PTH > little calcium affects NS

Question 39

Where are thymosins released, its target organ and its effects

Answer 39

Thymus Targets t lymphocytes stimulates development and maturation

Question 40

What are the two parts of the adrenal gland

Answer 40

medulla cortex

Question 41

Where is adrenaline and noradrenalin released, its target organ and its effects

Answer 41

medulla most tissues prepares for flight or fight, reinforces sympathetic NS + increase glucose levels

Question 42

what does the adrenal cortex release

Answer 42

corticosteriods aldosterone cortisol

Question 43

Where is aldosterone released, its target organ and its effects

Answer 43

a Cortex kidney reabsorption of Na and excretion of K

Question 44

Where is cortisol released, its target organ and its effects

Answer 44

a cortex most cells promotes normal metabolism, helps body deal with stress, repair of damaged cells

Question 45

What are the endocrine and exocrine roles of the pancreas

Answer 45

- Exocrine Role: Secretes digestive enzymes into small intestines through pancreatic ducts - Endocrine Role: maintain glucose levels

Question 46

Where is insulin released, its target organ and its effects

Answer 46

pancreas most cells uptake of glucose = lowers levels

Question 47

Where is glucagon released, its target organ and its effects

Answer 47

pancreas liver and fat storage breakdown of glycogen and fat= increase levels of glucose

Question 48

Where is androgens released, its target organ and its effects

Answer 48

testes many tissues male characteristics

Question 49

Where is oestrogens released, its target organ and its effects

Answer 49

ovaries many tissues female characteristics

Question 50

Where is progesterone released, its target organ and its effects

Answer 50

ovaries uturus and mamammary glands prepare for milk secretion, regulates menstrual cycle

Question 51

What does the kidney secrete and what does it do

Answer 51

- (EPO) stimulates production of RBC in bone o Athletes take EPO as increase RBC count (which carry oxygen to muscles) to improve aerobic ability, delay fatigue