Ex Phys Midterm Pure Recall

Homeostasis

Maintenance of a relatively constant internal environment (the body's regulated variables stay within a narrow range).

Steady state

A constant internal environment that is not necessarily normal (e.g., steady heart rate and VO2 during constant-load exercise).

Energy

The capacity to do work.

Metabolism

The total of all chemical reactions in the body, including both energy-releasing (catabolic) and energy-building (anabolic) reactions.

Coupled reactions

Reactions linked so that energy released by one (like ATP breakdown) drives another that needs energy.

Rate-limiting enzyme of glycolysis

Phosphofructokinase (PFK). Hexokinase and pyruvate kinase also help regulate the pathway.

Respiratory exchange ratio (RER)

VCO2 divided by VO2. It estimates which fuel is being burned.

RER of 0.70

Fat is the primary fuel being oxidized.

RER of 1.00

Carbohydrate is the primary fuel being oxidized.

RER of about 0.85

A mix of roughly equal fat and carbohydrate use.

IL-6

A myokine released by contracting skeletal muscle. It acts locally and systemically (e.g., helps with glucose uptake and fat breakdown).

Myokine

A signaling protein released by skeletal muscle during contraction that affects the muscle itself and other tissues.

Anterior pituitary hormones

Growth hormone (GH), ACTH, TSH, prolactin, FSH, LH.

Posterior pituitary hormones

ADH (vasopressin) and oxytocin.

Adrenal cortex hormones

Cortisol and aldosterone.

Adrenal medulla hormones

Epinephrine and norepinephrine.

Pancreas hormones

Insulin (beta cells) and glucagon (alpha cells).

Thyroid hormones

Thyroxine (T4), triiodothyronine (T3), and calcitonin.

Which gland releases growth hormone?

Anterior pituitary

Which gland releases cortisol?

Adrenal cortex

Which gland releases epinephrine and norepinephrine?

Adrenal medulla

Which gland releases insulin and glucagon?

Pancreas

Dendrites

Branch-like extensions of the neuron that receive incoming signals.

Cell body (soma)

Contains the nucleus and organelles. It integrates incoming signals.

Axon hillock

Region where the axon meets the cell body. It is where the action potential is initiated.

Axon

Long fiber that carries the action potential away from the cell body.

Myelin sheath

Fatty insulating layer around the axon that speeds up conduction.

Nodes of Ranvier

Gaps in the myelin sheath where the action potential regenerates (saltatory conduction).

Axon terminals

Ends of the axon that release neurotransmitter onto the next cell.