Endo

Question 1

What are the different types of cell to cell communication

Answer 1

1. Direct
   - gap junctions
   - cell membrane proteins
2. Indirect
   - paracrine
   - autocrine
   - endocrine
   - neurocrine

Question 2

Differences between endocrine + nervous communications

Answer 2

Endo released from glands / cells, nerv released from neurons
Endo slower acting, longer lasting
Nerv rapid transmission, short-lived

Question 3

Define

1. endocrine
2. paracrine
3. autocrine
4. neurocrine

Answer 3

1. secreted from cell / gland into blood
2. acts on adjacent cell
3. acts on same cell chemical is released from
4. neurotransmitter released from neuron

Question 4

Explain how target cells are active participants in cell to cell communications

Answer 4

ligand binds
intracellular signalling proteins
effector proteins causing desired result

Question 5

What is a second messenger?

Answer 5

Intracellular signaling molecules released by the cell when triggered by extracellular signaling molecules—the first messengers. Second messengers trigger physiological changes

Metabotropic receptor responses activate amplifier enzymes that create intracellular second messengers

Question 6

Name the different second messengers

Answer 6

Calcium
Cyclic AMP (cAMP)
Cyclic GMP (cGMP)
Inositol triphosphate (IP3)
Diaceyl glycerol (DAG)

Question 7

Name major endocrine glands (8)

Answer 7

Hypothalamus
Pituitary
Thyroid
Parathyroid
Thymus
Adrenal
Pancreas
Gonads

Question 8

Name secondary endocrine glands (4)

Answer 8

Heart
Kidney
Adipose Tissue
Stomach

Question 9

Distinguish between exocrine + endocrine glands

Answer 9

Exocrine: secreted into duct
Endocrine: secreted into blood

Question 10

How are nervous + endocrine alike + different?

Answer 10

Both transmit messengers

Difference:

• nerves closer proximity vs endocrine into blood
• nerves = neurotransmitters, endo = hormones
• nerves = rapid + short-lived, endo=longer for change to occur but sustained

Question 11

Classes of hormones

Answer 11

1. Proteins + polypeptides
2. Steroid hormones
3. Derivatives of AA tyrosine
   - catecholamines
   - thyroid

Question 12

how steroid and non-steroid hormones are synthesized

Answer 12

Steroid: from cholesterol
synthesis is in mitochondria
all derived from choleterol -> from pregnenolone

Protein: prehormone by ribosomes on rough ER + cleaved to prohoromones

• > golgi (packaged)
• > secretory vesicles (stored)

Question 13

How how steroid and non-steroid hormones affect target cells

Answer 13

Steroid: lipophillic = diffuse through membrane -> intracellular receptors

Non-steroid (protein) = lipophobic = protein receptors

Question 14

How negative feedback mechanisms regulate hormonal secretions

Answer 14

Long-loop: Target gland -> hypothalamus / pituitary

Short-loop: pituitary -> hypothalamus

Ultrushort-loop -> hypothalamic hormone inhibited by the same hormone

Question 15

Hormone actions of plasma membrane receptors vs intracellular receptors

Answer 15

Plasma membrane activates second messenger inside cell

Intracellular messengers are already inside of cell