Homeostasis and Feedback Mechanisms

Flashcards covering the key concepts of homeostasis, negative feedback, and positive feedback mechanisms discussed in the lecture notes.

What is homeostasis?

The process by which the body maintains a stable internal environment despite external changes.

What are the key aspects of homeostasis?

Regulating body temperature, maintaining water balance, controlling oxygen and carbon dioxide levels, stabilizing blood glucose levels, regulating hormone levels, and balancing blood pH levels.

What do negative feedback loops do?

Counteract changes and restore balance in the body.

What acts as a thermostat for the body?

The hypothalamus

What happens when the body is hot to regulate temperature?

Blood vessels dilate (vasodilation), sweating increases.

What happens when the body is cold to regulate temperature?

Blood vessels constrict (vasoconstriction), and the body starts shivering.

What regulates water levels by filtering excess fluid through urine?

The kidneys

What happens to ADH levels during dehydration?

Increased release of antidiuretic hormone (ADH) to retain water.

What happens to ADH levels with excess water intake?

Decreased ADH production to remove excess fluid.

What does the respiratory system control in gas exchange?

Controls oxygen intake and carbon dioxide removal.

What happens to breathing rate when oxygen levels are low?

Faster breathing rate to increase oxygen absorption.

What happens to respiratory activity when carbon dioxide levels are high?

Increased respiratory activity to expel CO₂.

What does the pancreas release to regulate blood glucose?

Insulin to lower blood glucose and glucagon to raise it.

What happens after eating regarding insulin and glucose?

Insulin triggers glucose absorption by cells.

What happens during fasting regarding glucagon and glucose?

Glucagon signals the release of stored glucose.

What happens when thyroid hormone levels are too low?

Thyroid-stimulating hormone (TSH) is produced to restore balance.

What organs help regulate blood pH?

Kidneys and lungs help regulate pH by excreting excess acids or bases.

How does breathing adjustment help regulate blood pH?

Faster breathing removes CO₂, reducing acidity.

What do positive feedback loops do?

Intensify a process rather than reverse it.

What hormone stimulates uterine contractions during labor?

Oxytocin stimulates stronger uterine contractions.

What causes rapid clot formation during blood clotting?

Platelets release chemicals that recruit more platelets.

How does global warming act as positive feedback?

Less ice reflects sunlight, more heat absorbed, further temperature rise occurs, and rising temperatures lead to more greenhouse gas release.

What is dynamic equilibrium?

A state of equilibrium in the body with respect to various functions and to the chemical compositions of fluids and tissues.

What is the role of the hypothalamus in thermoregulation?

The organ responsible for detecting changes in body temperature and triggering responses to maintain stable temperature.

What is hyperthermia?

Condition in which the body temperature is dangerously high, often due to prolonged exposure to heat or overproduction of body heat.

What is hypothermia?

Condition in which the body temperature is dangerously low, often due to prolonged exposure to cold.

What is osmoregulation?

The process by which the kidneys filter blood, reabsorb essential substances, and excrete waste products and excess water as urine.

What is the role of antidiuretic hormone (ADH) in maintaining water balance?

A hormone that helps regulate water balance by signaling the kidneys to retain water, thus concentrating urine.

What is diabetes insipidus?

A condition characterized by excessive thirst and frequent urination, often due to problems with ADH or kidney function.

What is the role of the respiratory system in maintaining gas exchange balance?

The process by which the lungs regulate the balance of oxygen and carbon dioxide in the blood through ventilation and gas exchange.

What is hypercapnia?

A condition characterized by abnormally high levels of carbon dioxide in the blood, often due to inadequate ventilation.

What is hypocapnia?

A condition characterized by abnormally low levels of carbon dioxide in the blood, often due to excessive ventilation.

What is the role of insulin in regulating blood glucose?

A hormone produced by the pancreas that lowers blood glucose levels by promoting the uptake of glucose by cells.

What is the role of glucagon in regulating blood glucose?

A hormone produced by the pancreas that raises blood glucose levels by stimulating the breakdown of glycogen in the liver.

What is diabetes mellitus?

A condition characterized by high blood glucose levels due to insufficient insulin production or insulin resistance.

What is the role of hormones in homeostasis?

Chemical messengers produced by endocrine glands that regulate various physiological processes, including metabolism, growth, and reproduction.

What is the function of the thyroid gland in hormonal regulation?

A gland in the neck that produces hormones (T3 and T4) which regulate metabolism, growth, and development.

What is acid-base balance?

The maintenance of a stable pH in the body fluids, which is crucial for enzyme function and cellular processes.

What is acidosis?

A condition in which the blood has excessive acid (low pH), often due to respiratory or metabolic disturbances.

What is alkalosis?

A condition in which the blood has excessive base (high pH), often due to respiratory or metabolic disturbances.

What are the implications of positive feedback loops in homeostasis?

A self-amplifying cycle in which a physiological change leads to an even greater change in the same direction.

What is the role of oxytocin in childbirth (a positive feedback loop)?

A hormone released during childbirth that intensifies uterine contractions and promotes milk ejection.

A rapid sequence of events triggered by blood vessel injury that leads to the formation of a blood clot to stop bleeding.