Kin 310: Lecture 5 - Cell Signaling & Hormonal Responses to Exercise

Vocabulary flashcards covering key hormones and concepts from Lecture 5 on cell signaling and hormonal responses to exercise.

Plasma glucose

Fuel source at all exercise intensities; maintained via glycogenolysis, gluconeogenesis, lipolysis, and regulated glucose utilization.

Glycogenolysis

Breakdown of glycogen to glucose to maintain plasma glucose during exercise (occurs in liver and muscle).

Gluconeogenesis

Synthesis of glucose from non-carbohydrate substrates during exercise (primarily in liver).

Lipolysis

Breakdown of triglycerides to glycerol and free fatty acids to fuel exercise.

Blocking glucose entry

Mechanism to decrease glucose entry into cells, helping preserve plasma glucose during exercise.

Permissive hormone

Hormone that increases action of other hormones by increasing receptor number or affinity (e.g., thyroid hormones increasing beta receptors for epinephrine).

Slow-acting hormone

Hormones with slower onset and longer-lasting effects during exercise (e.g., cortisol, growth hormone).

Fast-acting hormone

Hormones with rapid effects during exercise (e.g., epinephrine, norepinephrine, glucagon).

Thyroid hormones

T3 and T4; regulate metabolism; exert permissive effects during exercise.

T3 (Triiodothyronine)

Active thyroid hormone; increases receptor sensitivity and metabolic rate; released from thyroid.

T4 (Thyroxine)

Precursor thyroid hormone; bound to carrier proteins in plasma; converted to T3.

Cortisol

Adrenal cortex glucocorticoid; stimulates glycogenolysis, gluconeogenesis, lipolysis; decreases glucose utilization; increases with exercise intensity.

Growth hormone

Secreted from anterior pituitary; potent stimulus for release during exercise; promotes glycogenolysis, gluconeogenesis, lipolysis; slow-acting.

Epinephrine

Catecholamine from adrenal medulla; fast-acting; stimulates glycogenolysis, gluconeogenesis, lipolysis; blocks glucose entry.

Norepinephrine

Catecholamine from adrenal medulla; similar actions to epinephrine; involved in fuel mobilization and glucose regulation; increases with exercise.

Insulin

Beta-cell hormone; decreases during exercise due to sympathetic activity; promotes glucose entry via GLUT4; activates hexokinase and glycogenesis.

Glucagon

Alpha-cell hormone; increases during exercise; promotes glycogenolysis, gluconeogenesis, lipolysis; decreases glucose utilization.

GLUT4

Insulin-responsive glucose transporter; translocates to cell membrane during exercise to increase glucose uptake.

Hexokinase

Enzyme that phosphorylates glucose to glucose-6-phosphate, trapping glucose in the cell; activated by insulin signaling.

Lactate and H+ effect on lipolysis

High lactate and hydrogen ions during intense exercise inhibit lipolysis by affecting hormone-sensitive lipase; training lowers lactate production, increasing reliance on FFAs.