Vertebrates 20 - Endocrine Flashcards Preview

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Flashcards in Vertebrates 20 - Endocrine Deck (21)
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1

5 ways of chemical signaling

Autocrine, paracrine, endocrine, neruoendocrine, exocrine

2

Endocrine

Go through bloodstream to travel to target

3

Neuroendocrine

Stimulated and release hormones into blood. Neurons from hypothalamus

4

Exocrine

Especially pheromones, sensed by another organism

5

Peptides and proteins

Small. Insulin, ADH. Bind to membrane receptors.

6

Amines

From amino acids, epinephrine and thyroxine. Bind to membrane receptors

7

Steroids

From cholesterol. Testosterone, estrogen, cortisol. Hydrophobic so they have carrier proteins and then diffuse through membrane

8

Pituitary gland/Hypophysis

Ant. and Post. Controlled by the hypothalamus

9

Hypothalamus

Homeostatic mechanisms: hunger, thirst, temp. Responds to brain inputs (stress, circadian rhythms, etc).

10

Anterior pituitary

Adenohypophysis. Releases TSH, FSH, LH, GH, Prolactin (milk and some brain), ACTH, MSH. Connected by a portal system to hypothalamus which sends hormone messages.

11

Posterior pituitary

Neurohypophysis. Nerves from hypothalamus enter and release hormones from there. ADH and oxytocin.

12

Agnatha endocrine

Hypothalamus, less obvious pituitary. No distinct adrenal or thyroid glands.

13

Chondrichthyes endocrine

More developed pituitary. Adrenal in separate places, cortex (suprarenal - cortisol) and medulla (interrenal - adrenalin).

14

Osteichthyes endocrine

Pituitary lacks portal system but has nerve connection to hypothalamus. Adrenal glands together but in multiple places.

15

Amphibian endocrine

Portal system present. thyroxine stimulates metamorphosis

16

Reptilia endocrine

One pair of adrenal glands

17

Aves endocrine

Prolactin stimulates crop milk (secretion to feed young in some birds). 10x Glucagon, more thyroxine for higher metabolism

18

Catabolic and anabolic pathways

Catabolic breaks down, so lower body weight (cortisol, thyroxine); anabolic builds (testoterone)

19

Know the thyroid, cortisol and testosterone axes

Hypo - TRH - Ant Pit - TSH - Thyroid - Thyroxine - shut off the others, increase metabolism. … ACTH - Adrenal - Cortisol - shut these off; Hypothalamus - GnRH - Ant Pit - LH - Testes - Testosterone - build muscle etc, turn off the other

20

Effects of hormones (general)

Cell response and also trophic effects (growth of cells)

21

Why use male castrated animals in endocrine testing?

Females have hormone cycles that can complicate results; castrate to eliminate testosterone