Week 4: Recorded Lectures

Question 1

Hydrophilic Signalling Factors

Answer 1

• Water loving
• When synthesized cannot cross cellular membranes
• Can be stored and released on demand

Question 2

Hydrophobic Signalling Factors

Answer 2

• Water hating
• When synthesized can cross cellular membranes
• Can’t be stored so they diffuse from the cell

Question 3

Hydrophilic Factors - Travel

Answer 3

Travel easily, dissolved in the extracellular fluid

Question 4

Hydrophobic Factors - Travel

Answer 4

Have to travel attached to a water-soluble carrier

Question 5

Water Soluble

Answer 5

• Can’t get into cell so they have to trigger a response by binding to a receptor on the cell membrane

Question 6

Fat Soluble

Answer 6

Freely diffuse across cell membrane, so receptors are inside the cell

Question 7

Elements of Endocrine Signaling Pathway

Answer 7

1. Synthesis
2. Secretion
3. Transport
4. Reception
5. Transduction
6. Response

Question 8

Synthesis (step 1)

Answer 8

A hormone is synthesized in an endocrine gland

Question 9

Secretion (step 2)

Answer 9

• Hormones are released
• Lipid soluble hormones diffuse through cellular membranes
• Water soluble hormones are released via the ER-Golgi system using exocytosis

Question 10

Transport (step 3)

Answer 10

• Hydrophilic hormones need no carriers, they dissolve in the blood
• Hydrophobic hormones bind to proteins in the blood, which carry them to target tissues

Question 11

Reception (step 4)

Answer 11

• Binds to a receptor at the target tissue
• 2 things can occur: conformational change, ligand specificity

Question 12

Conformational Change

Answer 12

Binds hormone on outside causing change in shape to the receptor

Question 13

Ligand specificity

Answer 13

The ability of a receptor to bind only to a specific ligand

Question 14

Phytoestrogens

Answer 14

• Estrogen-like compounds found in plants
• In many vertebrates, males that eat too many plants may experience a feminization

Question 15

Transduction (step 5)

Answer 15

• Process of converting a signal into a cellular response
• Amplifying the signal
• Examples: cascades and 2nd messengers

Question 16

Antagonistic Hormones

Answer 16

Pairs of hormones that have opposite effects to maintain balance in the body

Question 17

What 2 main hormones control glucose levels?

Answer 17

• Insulin
• Glucagon

Question 18

Insulin

Answer 18

Reduces blood glucose levels when they’re high

Question 19

Glucagon

Answer 19

Increase blood glucose when they are low

Question 20

Hypothalamus gland

Answer 20

Collection of neurons

Question 21

Exocrine glands

Answer 21

Secretes products outside of the body

Question 22

Endocrine glands

Answer 22

Secretes hormones into the circulating fluids, blood or ECF

Question 23

Posterior pituitary

Answer 23

Collection of terminal axons coming from hypothalamus

Question 24

Anterior pituitary

Answer 24

Communicates with hypothalamus via portal vessel

Question 25

Portal vessel

Answer 25

Blood vessels that don't fit definition of artery or vein

Question 26

Adrenal Glands

Answer 26

- Found on the kidneys - Secrete epinephrine apart of adrenal response

Question 27

Myocytes

Answer 27

- Muscle cells - Contractile cells in muscles regulate physiological systems and are essential for homeostasis

Question 28

Microtubules

Answer 28

- Biggest - Tubulin polymers - Serve as tracks for motor proteins to walk

Question 29

Microfilaments

Answer 29

- Smallest - Actin filaments - Maintain cell shape, enable cell movement, and assist in cell division.

Question 30

Intermediate Filaments

Answer 30

- Middle size - One of several proteins like keratin

Question 31

Myosin & Actin

Answer 31

- In all eukaryotic cells and all animal cells as apart of the cytoskeleton - Myosin walk along actin filaments

Question 32

Kinesin

Answer 32

- walks along microtubule tracks - Recognize polarity of microtubules. One walks towards (+) end, and the other walks toward (-) end

Question 33

Dynein

Answer 33

- walks along microtubule tracks - Recognize polarity of microtubules. One walks towards (+) end, and the other walks toward (-) end

Question 34

Myosin II

Answer 34

- made up of a head, tail and neck - Proteins @ neck help regulate catalytic properties of myosin

Question 35

Thin filaments

Answer 35

- actin filaments in a myocyte - arranged into an array - decorated with actin binding proteins: troponin and tropomyosin

Question 36

Thick filaments

Answer 36

- Myosin's arranged into bundles

Question 37

Smooth muscle

Answer 37

- Has thick and thin filaments - They are scattered throughout the cell in all directions

Question 38

Sarcomeres

Answer 38

- Basic contractile units of muscle fibre

Question 39

Myofibrils

Answer 39

- long, cylindrical structures found within muscle fibers - contain actin and myosin, enabling muscle contraction

Question 40

Actomyosin ATPase

Answer 40

- Enzyme that hydrolyzes ATP to provide energy for muscle contraction

Question 41

Troponin

Answer 41

protein complex bound to actin that controls muscle contraction by responding to calcium ions

Question 42

Tropomyosin

Answer 42

protein that blocks myosin-binding sites on actin filaments, preventing contraction until troponin induces a change

Question 43

Innervation patterns

Answer 43

Determine where a muscle contracts once or has a sustained contraction

Question 44

Muscle recruitment

Answer 44

Determines the contractile force

Question 45

Antagonistic groups

Answer 45

- pairs of muscles that work opposite to each other, where one contracts while the other relaxes - Ex. Biceps and triceps