Homeostasis and Feedback Mechanisms in Human Body

Homeostasis

The way our body keeps a stable internal environment, even if the outside world changes.

Negative feedback

Constant adjustments to maintain setpoint; body counteracts a changing variable (stimulus).

Positive feedback

When the body intensifies the variable, such as during labor/delivery.

Stimulus

A variable that triggers a response in the body.

Response

The action taken by the body in reaction to a stimulus.

Regulation

The process of maintaining balance in the body.

Feedback loop

A system that uses feedback to maintain homeostasis.

Temperature regulation

The process of maintaining a stable body temperature despite external temperature changes.

Blood sugar control

The regulation of glucose levels in the blood to maintain homeostasis.

Childbirth

An example of positive feedback where contractions intensify to facilitate delivery.

Vasoconstriction

The narrowing of blood vessels to redirect blood flow, often in response to cold.

Vasodilation

The widening of blood vessels to redirect blood flow, often in response to heat.

Shivering

A response to cold that generates heat to maintain body temperature.

Sweating

A response to heat that helps cool the body down.

Circulatory system

The system responsible for pumping blood through the body and distributing materials.

Respiratory system

The system responsible for inhaling oxygen and exhaling carbon dioxide.

Setpoint

The ideal value or range that the body tries to maintain for various physiological parameters.

Oscillation around set point

The process of fluctuating around a setpoint due to negative feedback mechanisms.

Internal Steady State

A condition where internal variables remain stable despite external changes.

Importance of Negative Feedback

It is important to the body because maintenance of homeostasis is crucial for life processes.

Importance of Positive Feedback

It is important to the body because it helps complete short-term processes.

Blood Sugar Regulation

After eating, blood sugar levels rise, and the pancreas releases insulin to lower them; this is negative feedback because it is a corrective mechanism.

Childbirth Contractions

During labor, oxytocin release intensifies uterine contractions; this is positive feedback because it intensifies the response until the baby is born.

Body Temperature Regulation

When body temperature increases, sensors trigger sweating to cool down; this is negative feedback because it is a corrective mechanism.

Blood Clotting

When a blood vessel is injured, platelets attract more platelets to form a clot; this is positive feedback because it intensifies the response to stop bleeding.

Breathing Rate

When carbon dioxide levels rise, the brain signals the lungs to increase breathing rate; this is negative feedback because it is a corrective mechanism.

Insulin

A hormone that helps lower blood sugar levels after eating.

Glucagon

A hormone that raises blood sugar levels when they drop too low.

Oxytocin

A hormone that stimulates uterine contractions during childbirth.

Platelets

Little cell fragments that help in blood clotting by attracting more platelets to the injury site.

Sensor

A part of the body that detects changes in the environment.

Short-term Processes

Processes that are completed quickly, often involving positive feedback.

Corrective Mechanism

A response that counteracts a change to restore balance.

Intensified Response

A response that increases in magnitude, often seen in positive feedback.

Lactation

When a baby suckles at the breast, it stimulates the release of the hormone prolactin, which increases milk production.

Example of negative feedback

When body temperature rises above normal, sweat glands release sweat, which cools the body as it evaporates.

Blood glucose regulation

When blood glucose levels are too high, insulin is released to drive glucose into cells; when too low, glucagon is released to break down glycogen to increase blood glucose to normal.

Childbirth feedback claim

This claim is false. Oxytocin increases contractions, pushes down baby, leading to more contractions.

Carbon dioxide levels during exercise

The increase in blood CO2 is the stimulus; the increase in breathing rate is the response to return to homeostasis.

Pain stimulus

You accidentally step on a sharp rock while walking barefoot. Stimulus: Pain; Response: Pull foot back.

Sound stimulus

A cat hears a loud noise and jumps away from the sound. Stimulus: Sound; Response: Jumps away.

Light stimulus

You walk outside on a bright, sunny day, and your eyes squint automatically. Stimulus: Light; Response: Squint.

Tropism movement

A sunflower turns to face the sun throughout the day as it moves across the sky. Stimulus: Light; Response: Tropism/movement.

Plant tropism

A plant's leaves bend toward a window where sunlight shines. Stimulus: Light; Response: Tropism/movement.

ATP

Adenosine Triphosphate

Carbon Dioxide

Gas molecule containing one carbon and two oxygens

Cellular Respiration

Process of converting glucose into ATP

Diffusion

Movement of substances based on concentration

Dynamic Equilibrium

Maintaining overall balance

Excretory System

System responsible for water balance

Gas Exchange

Inhaling oxygen and exhaling carbon dioxide

Glucose

Sugar

Hypertonic

A solution with a higher concentration of solutes compared to another solution

Hypotonic

A solution with a lower concentration of solutes compared to another solution

Isotonic

A solution with an equal concentration of solutes compared to another solution

Metabolic Process

Chemical reactions that occur within a cell to maintain life

Mitochondria

Organelles known as the powerhouse of the cell, where ATP is produced

Nervous System

The body system responsible for transmitting signals between different parts of the body

Osmoregulation

The process of maintaining water balance in the body

Osmosis

The diffusion of water across a selectively permeable membrane

Oxygen

A gas essential for cellular respiration

Thermoregulation

The process of maintaining an optimal body temperature