General Biology 2: Examples of Homeostasis

(12-02-2025)

Osmosis

-This is the movement of water across the plasma membrane. -Cells maintain homeostasis using active and passive transport.

Plasma Membrane

also called the cell membrane, is the thin, flexible barrier that surrounds every cell.

• Helps to maintain a cell’s homeostasis.

•It is a thin, flexible boundary between a cell and its environment that allows nutrients into the cells and allows waste and other products to leave the cell.

Gatekeeper

The Cell Membrane acts like the “__________” of the cell.

Protects the Cell, Controls what enters and leaves the cell, helps maintain homeostasis, communication, and structure

5 Functions of the Plasma Membrane:

Phospholipid Bilayer

The plasma membrane is made of the:

Phosphate head and lipid tail

2 Parts of the Phospholipid bilayer:

Phosphate Head

This part of the phospholipid bilayer loves water (hydrophilic)

Lipid Tail

This part of the phospholipid bilayer hates water (hydrophobic)

Active and Passive Transport

2 Types of Transport Across the Membrane:

Passive Transport

Type of transport where: (No Energy Required)

Active Transport

Type of Transport where: (Uses Energy/ATP)

Na+/K+ ATPase pump

This is an active transport protein which is found in the plasma membrane of animals.

Its main function is to maintain the level of Sodium (Na+) ions and potassium (K+) inside and outside the cell.

Maintaining homeostasis, Maintaining resting membrane potential, Preventing cell swelling and Transport of nutrients

Why the Na+/K+ATP is important?

Temperature Regulation

the process by which the body keeps its internal temperature constant, usually around 37°C (98.6°F), even if the outside temperature changes.

Sweating, Vasodilation, and Decreased Muscle Activity

3 Ways When the body gets TOO HOT

Sweating

Sweat glands release sweat.

Vasodilation

Blood vessels near the skin surface widen.

Decreased Muscle Activity

The body reduces heat production.

Shivering, Vasoconstriction, Goosebumps, and Increased Metabolism

4 Processes When the body gets TOO COLD:

Shivering

Muscles contract quickly

Vasoconstriction

Blood vessels near the skin narrow.

Goosebumps

Hair stands up slightly.

Increased Metabolism

The body burns more energy to produce heat.

Skin

In mammals, ____ is the major organ for regulating body temperature.

Poikilotherms and Homeotherms

2 Kinds of organisms for temperature regulation:

Poikilotherms

Having a body temperature that varies or changes with the environment; cold blooded organisms.

Homeotherms

Having a constant body temperature despite fluctuations in environmental temperature; warm-blooded organisms.

Endocrine System

•This system helps maintaining homeostasis with signals from internal mechanisms called negative feedback.

•It is made up of glands that produce (), which act as chemical messengers that travel through the blood to control many body functions.

Hormones

•It is made up of glands that produce _________, which act as chemical messengers that travel through the blood to control many body functions.

Pituitary Gland

Controls other glands; regulates growth, water balance, and reproduction hormones.

Master Gland

The Pituitary Gland is also known as: ______ _____.

Hypothalamus

Links the nervous system and endocrine system; controls hunger, thirst, and temperature.

Thyroid Gland

Controls metabolism, energy levels, and body temperature

Parathyroid Glands

Regulate calcium levels in the blood.

Adrenal Glands

Produce adrenaline and cortisol; help the body respond to stress.

Pancreas

Controls blood sugar by producing Insulin and Glucagon.

insulin

It is released when your blood sugar is too high, it’s purpose is (lowers blood sugar)

Glucagon

It is released when your blood sugar is too low, it’s purpose is (raises blood sugar)

Ovaries

Produce estrogen and progesterone; control menstrual cycle and female traits.

Testes

Produce testosterone; control male traits and sperm production