Introductory Concepts

Question 1

Homeostasis

Answer 1

Maintenance of a stable internal environment; a dynamic state of equilibrium necessary to sustain life

Question 2

Homeostatic imbalance

Answer 2

Disturbance in homeostasis resulting in stress or disease

Question 3

Levels of structural organization for homeostasis

Answer 3

Atoms → cells → tissues → organs → systems → organism

Question 4

Primary mediator of short-term changes

Answer 4

Neural

Question 5

Primary mediator of long-term changes

Answer 5

Hormonal

Question 6

Claude Bernard

Answer 6

Stated that integument separates internal and external environments, and that organ systems allow movement between these environments

Question 7

Homeostatic control relies on:

Answer 7

Constant monitoring of the composition of blood by sensory systems, responses to changes in blood by response systems, and negative feedback

Question 8

Parts of the homeostatic system

Answer 8

Receptor, control centre, and effector

Question 9

Receptor component

Answer 9

Sensor and integrator; responds to stimuli and sends info to control centre

Question 10

Control centre component

Answer 10

Determines set point, analyzes info from receptor and relays the appropriate response to the effector organ

Question 11

Effector component

Answer 11

Provides a means for response to the stimulus

Question 12

Negative feedback

Answer 12

Most homeostatic control mechanisms; shuts off original stimulus or decreases intensity

Question 13

Positive feedback

Answer 13

Increases the original stimulus to push the variable farther and rapidly terminate a process

Question 14

Properties of nervous system

Answer 14

Uses electrochemical signals and synaptic transmission for very rapid responses

Question 15

Properties of endocrine system

Answer 15

Uses chemical messengers in extracellular fluids that can act over long periods of time and re-program tissues

Question 16

Nervous and endocrine integration

Answer 16

Endocrine tissues are integrated and some neutrons produce hormones

Question 17

Endocrine physiology

Answer 17

The study of hormones and their actions, and how endocrine glands regulate animals

Question 18

Endocrine gland

Answer 18

Tissue which releases a substance into the blood stream, which then travels via the blood to influence a target cell

Question 19

Hormones

Answer 19

Regulatory molecules secreted into extracellular fluid by endocrine secretory cells and act on target cells via receptor proteins

Question 20

Classes of hormones

Answer 20

Amino acid derivatives, peptides, proteins, steroids, fatty acid derivatives

Question 21

Intracrine

Answer 21

Secretory cell = target cell; autocrine

Question 22

Juxtacrine

Answer 22

Target cells are adjacent to secretory cells; paracrine

Question 23

Endocrine

Answer 23

Secretory cell sends hormones through vascular system to target cell

Question 24

Synthesis of protein, peptide, and aminergic hormones

Answer 24

Starts as mRNA in the nucleus, becomes prehormone in the RER, prohormone in golgi, and hormone in secretory granules where it is exocytosed after membrane depolarization and calcium influx

Question 25

Synthesis of steroid hormones

Answer 25

Synthesized in SER and mitochondria and diffuse out immediately

Question 26

Modes of secretion of hormones

Answer 26

Phasic, episodic, circadian/cyclic/circannual, mixed

Question 27

Control of hormone availability and potency

Answer 27

Neuroendocrine reflexes and feedback loops, post-Translational processing, storage and transport, receptors

Question 28

Etiology of endocrine diseases

Answer 28

Hypersecretion or overproduction, hyposecretion or underproduction, transport or clearance problems, hormone resistance

Question 29

Categories of regulating molecules

Answer 29

Hormones, pheromones, neurotransmitters, GFs, angiogenesis regulating molecules, cytokines

Question 30

The receptor theory

Answer 30

Hormones bind non-covalently to receptors in target cells, most often found in the plasma membrane except for steroid and thyroid hormones

Question 31

3 possible locations for receptors

Answer 31

Transmembrane, cytoplasm, nucleus

Question 32

Transmembrane receptors

Answer 32

Hormone binds extracellularly and activates pathways involving phosphorylation and enzyme activation, sometimes activating proteins (can have genomic and non-genomic effects)

Question 33

Intracellular receptors

Answer 33

Hormone binds to intracellular receptor and this complex acts as a transcription factor

Question 34

Types of transmembrane receptors

Answer 34

Ion channels, tyrosine kinase, cytokine receptors, g-protein linked

Question 35

Ion channels

Answer 35

Simplest type of transmembrane receptor; hormone binds and causes change in the transport of substances to change membrane potential

Question 36

Tyrosine kinase receptors

Answer 36

Ligand binds receptor → dimerization of receptor → protein phosphorylation cascade (non-genomic effects)

Question 37

Cytokine receptors

Answer 37

JAK II binds to the receptor, and when hormone binds, STATs are phosphorylated and result in modified gene expression

Question 38

G-protein linked receptors

Answer 38

7-transmembrane receptors that bind hormones, releasing Galpha, which activates a plasma membrane enzyme such as adenylate cyclase

Question 39

Adenylate cyclase

Answer 39

Turns ATP into cAMP, which with activate protein kinases or transcription factors

Question 40

Phospholipase C

Answer 40

Plasma membrane enzyme activated by GPCRs which breaks PIP2 into DAG and IP3

Question 41

DAG

Answer 41

Activates protein kinase C

Question 42

IP3

Answer 42

Causes calcium release from the endoplasmic reticulum

Question 43

Intracellular receptor mechanism

Answer 43

Bind to promoter region and cause conformational change that activates RNA polymerase 2 to start transcribing

Question 44

Types of receptors with genomic effects

Answer 44

Some cytoplasmic and all nuclear