HOMEOSTASIS & BODY FUNCTIONS

What is homeostasis?

maintenance of a relatively stable internal environment.

The ECF

is the internal environment of the body

External and Internal Environments

• The external environment surrounds the organism, while the internal environment is the extracellular fluid (ECF) that surrounds cells. The ECF includes plasma (the fluid portion of blood) and interstitial fluid, which bathes cells.

• Body systems exchange materials between the internal and external environments to sustain cellular functions.

Which body systems contribute to homeostasis by transporting materials?

The circulatory, respiratory, and digestive systems.

How does the body respond to a cold external environment to maintain homeostasis?

he temperature control center in the brain triggers shivering to generate heat.

Examples of factors regulated by homeostasis

Concentration of nutrients.

❑ Concentration of O2 and CO2.

❑ Concentration of waste products.

❑ pH.

❑ Concentration of water, salt, and other electrolytes

. ❑ Volume and pressure.

❑ Temperature.

Various body systems contribute to homeostasis:

• Circulatory system:

• Digestive system:

• Respiratory system:

• Urinary system:

• Skeletal and muscular systems:

• Integumentary system:

• Immune system: .

• Nervous and endocrine systems:

Circulatory system:

Transports materials like nutrients, oxygen, wastes, electrolytes, and hormones.

Digestive system:

Breaks down food into absorbable nutrients, transfers water and electrolytes, and eliminates waste.

Respiratory system:

Regulates oxygen intake, carbon dioxide removal, and helps maintain pH.

Urinary system:

Removes excess water, salts, and electrolytes, and maintains pH.

Skeletal and muscular systems:

Support movement and body structure, with muscles helping regulate temperature via heat generation.

Integumentary system:

Provides an external barrier and regulates temperature.

Immune system:

Defends against foreign invaders and repairs tissues.

Nervous and endocrine systems:

Serve as major regulatory systems to control body functions.

eg. important in controlling the concentration of nutrients and, by adjusting kidney function, controlling the volume and electrolyte composition of the ECF

To maintain homeostasis, the control system must be able to

• detect deviations from normal in the internal environmental.

• Integrate this information with any other relevant information.

• Make appropriate adjustments in the activity of the body parts responsible for restoring the deviated factor to its desired value.

What are intrinsic and extrinsic controls in homeostatic regulation?

Intrinsic controls are local to tissues, while extrinsic controls involve the nervous and endocrine systems.

What are the two main types of feedback mechanisms?

Negative feedback and positive feedback.

Give an example of a positive feedback mechanism.

Oxytocin release during childbirth.

What can happen if the kidneys fail to maintain homeostasis?

It may lead to fluid retention, high potassium levels, anemia, and weakened bones.

Positive feedback mechanism

output enhances or amplifies a change so that the controlled variable continues to move in the direction of the initial change.

The negative feedback

corrective adjustment opposes the original deviation from the normal desired level.