Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Physiology Stack 2
| Question | Answer |
|---|---|
| What maintains the resting membrane potential of a neuron? | The sodium–potassium pump (Na⁺/K⁺-ATPase), which moves 3 Na⁺ out and 2 K⁺ in, creating an electrochemical gradient. |
| What event triggers the rapid depolarization phase of an action potential? | Voltage-gated sodium channels opening, allowing Na⁺ to enter the cell. |
| What is saltatory conduction? | The jumping of action potentials between nodes of Ranvier on myelinated axons, greatly increasing conduction velocity. |
| What causes repolarization in an action potential? | Opening of voltage-gated potassium channels and efflux of K⁺. |
| What determines the strength of a neural signal? | Frequency of action potentials, since amplitude is constant (all-or-none principle). |
| How does the sympathetic nervous system affect heart rate and blood pressure? | It increases both by releasing norepinephrine, which binds to β₁ receptors in the heart. |
| What neurotransmitter is released by parasympathetic postganglionic neurons? | Acetylcholine (ACh), which acts on muscarinic receptors. |
| What is the functional role of the hypothalamus? | It regulates homeostasis: temperature, hunger, thirst, circadian rhythms, and autonomic/endocrine integration. |
| What is sensory transduction? | Conversion of a physical stimulus (light, sound, chemicals) into an electrical signal in sensory receptors. |
| How do steroid hormones exert their effects? | By diffusing through the cell membrane and binding intracellular receptors that alter gene transcription. |
| How are peptide hormones transported in the blood? | They circulate freely (unbound) because they are water-soluble. |
| What feedback mechanism regulates most endocrine hormones? | Negative feedback loops that maintain stable internal conditions. |
| What determines cardiac output? | Heart rate × stroke volume. |
| What is the role of preload in cardiac function? | It stretches cardiac muscle fibers before contraction; increased preload enhances stroke volume (Frank–Starling law). |
| What physiologically causes the “lub-dub” heart sounds? | S1: closure of AV valves; S2: closure of semilunar valves. |
| What initiates the electrical conduction of the heart? | The sinoatrial (SA) node, the heart’s natural pacemaker. |
| What is the primary function of the lymphatic system? | To return interstitial fluid to the bloodstream and support immune surveillance. |
| What is the difference between innate and adaptive immunity? | Innate immunity is fast and non-specific; adaptive immunity is slower, highly specific, and involves memory. |
| How do cytotoxic T cells kill infected cells? | By releasing perforin and granzymes that induce apoptosis. |
| What drives oxygen diffusion from alveoli into blood? | A partial pressure gradient, with alveolar PO₂ higher than pulmonary capillary PO₂. |
Created by:
Harriet Afriyie
Popular Biology sets