Question

review questions

1. what are the basic characteristics of human life activities?
2. what are the definitions of different mode of hormone action?
3. please explain the difference of humoral regulation and nervous regulation?

Explanation:

Question 1

Human life activities have several basic characteristics: 1. Metabolism: It includes anabolism (synthesis of complex substances) and catabolism (breakdown of complex substances) to maintain life. 2. Irritability: The ability to respond to internal and external stimuli. 3. Adaptability: Adjusting to the environment to survive. 4. Growth and development: Increase in size, complexity, and functional maturity. 5. Reproduction: Producing offspring to ensure species continuity.

• Endocrine action: Hormones are released into the bloodstream and act on target cells at distant sites (e.g., thyroid hormones acting on multiple tissues).
• Paracrine action: Hormones act on neighboring cells (e.g., somatostatin from delta cells in pancreas acting on adjacent alpha/beta cells).
• Autocrine action: Hormones act on the same cell that secreted them (e.g., some growth factors stimulating the cell that produced them).
• Neurocrine (Neuroendocrine) action: Neurons secrete hormones into the bloodstream (e.g., hypothalamic neurons secreting releasing hormones into portal circulation).
• Juxtacrine action: Hormones (or signaling molecules) act through direct cell - cell contact (e.g., some cell - surface - bound growth factors acting on adjacent cells with appropriate receptors).

Aspect	Humoral Regulation	Nervous Regulation
Transmission Route	Through the bloodstream (for endocrine hormones) or interstitial fluid (for paracrine factors)	Through neurons (via axons) and synapses
Speed of Action	Generally slower (hormones need to be transported and have longer - lasting effects)	Very fast (nerve impulses travel quickly, and neurotransmission at synapses is rapid)
Duration of Action	Longer - lasting (hormones can circulate and act for minutes to hours or even days)	Short - lived (neurotransmitters act briefly at synapses, and the effect ends quickly)
Specificity	Acts on target cells with specific receptors (may be widespread or localized depending on hormone)	Acts on specific target organs/tissues innervated by the neuron
Initiation of Response	Triggered by changes in blood - borne substances or internal/external stimuli that affect endocrine glands	Triggered by sensory stimuli or internal neural signals, leading to action potentials in neurons

In summary, humoral regulation uses chemical messengers, is slower, has longer - lasting effects, and acts via the circulatory or interstitial fluid system. Nervous regulation uses nerve impulses and neurotransmitters, is very fast, has short - lived effects, and acts via neurons and synapses.

Answer:

The basic characteristics of human life activities are metabolism (including anabolism and catabolism), irritability (response to stimuli), adaptability (adjust to environment), growth and development (increase in size/complexity/maturity), and reproduction (produce offspring).

Question 2