Hormones, Homeostasis, and Body Regulation Mechanisms

What are the main differences between protein hormones and steroid hormones?

Protein hormones are hydrophilic and cannot easily diffuse through the plasma membrane, relying on membrane receptors. Steroid hormones are hydrophobic, can diffuse across the membrane, and have receptors inside the nucleus or cytosol.

What is homeostasis?

Homeostasis is the maintenance of a stable internal environment in an organism, essential for survival.

Why is homeostasis important for the functioning of an organism?

Homeostasis ensures optimal conditions for enzyme activity, maintains cell function, regulates blood glucose levels, body temperature, balances gases for respiration, supports immune function, allows adaptation to stress, and prevents organ damage.

What are the components of the stimulus response model?

The components include: Stimulus (change), Receptor (detects change), Modulator (processes information), Effector (responds to signal), Response (change in function).

What is the difference between negative feedback and positive feedback mechanisms?

Negative feedback counteracts a stimulus to restore balance (e.g., sweating), while positive feedback amplifies the stimulus and is rare in homeostasis (e.g., labor contractions).

What is thermoregulation and its significance?

Thermoregulation is the regulation of body temperature, vital for maintaining stable protein function and enzyme activity.

How does the body respond to high temperatures?

Responses include convection, conduction, radiation, and evaporation to increase heat loss.

What mechanisms produce heat in the body?

Shivering and brown adipose tissue metabolism generate heat by increasing muscle activity and metabolic processes.

How is glucose regulated in the bloodstream when levels are high?

Beta cells in the pancreas secrete insulin, which prompts skeletal muscle and fat cells to absorb glucose and stimulates the liver to convert glucose to glycogen.

What happens when blood glucose levels are low?

Alpha cells in the pancreas secrete glucagon, stimulating the liver to convert glycogen back to glucose and release it into the bloodstream.

What are the symptoms of hypothermia?

Symptoms include shivering, slurred speech, slow breathing and heart rate, confusion, cold skin, and in severe cases, unconsciousness or death.

What causes hyperthermia?

Hyperthermia occurs when body temperature rises above 38°C due to the body's failure to lose excess heat, often in hot, humid conditions.

What are the symptoms of hyperthermia?

Symptoms include heavy sweating, rapid heartbeat, dizziness, headache, muscle cramps, confusion, and in extreme cases, seizures or death.

What role does the pancreas play in homeostasis?

The pancreas produces and releases hormones, particularly insulin and glucagon, to regulate blood sugar levels.

What hormones does the thyroid gland secrete, and what are their effects?

The thyroid gland secretes T3 and T4, which regulate metabolism, growth, and development, increasing metabolic rate and cardiac output.

What is the function of the hypothalamus in homeostasis?

The hypothalamus acts as the central coordinating hub for maintaining the body's homeostasis.

What is the role of receptors in the homeostatic mechanism?

Receptors detect changes in the internal or external environment, initiating the homeostatic response.

What is the function of effectors in the stimulus response model?

Effectors are molecules, cells, or organs that respond to signals from modulators to initiate an action.

How does the body maintain stable blood glucose levels?

The body maintains stable blood glucose levels through the actions of insulin and glucagon, which regulate glucose uptake and storage.

What is the significance of feedback loops in homeostasis?

Feedback loops, especially negative feedback, are crucial for maintaining stability in physiological processes.

How does the body adapt to stress or environmental changes?

The body adapts through mechanisms like sweating to cool down or altering metabolic rates to respond to different conditions.

What is the role of brown adipose tissue in thermoregulation?

Brown adipose tissue generates heat through metabolism, contributing to the body's ability to maintain temperature.

What are thermoreceptors and their function?

Thermoreceptors detect temperature changes and send signals to the hypothalamus to regulate body temperature.

What is glycogen and where is it stored?

Glycogen is a polymer of glucose stored in the liver, serving as a form of energy reserve.

What happens to enzymes at extreme temperatures?

Enzymes can denature at high temperatures and become inactive at low temperatures, affecting metabolic processes.

What is the importance of maintaining blood pH within a narrow range?

Maintaining blood pH is crucial for enzyme function and overall metabolic processes.