Human Physiology Introduction

Study Notes

Definition of Human Physiology

Human physiology studies normal functions of body parts and mechanisms that sustain life.

Organization of the Human Body

Comprised of systems, organs, tissues, and cells.

Body Systems

Nervous system: Brain, spinal cord, and nerves.
Endocrine system: Consists of various endocrine glands.
Cardiovascular system: Includes the heart and blood vessels.
Respiratory system: Comprises structures such as the nose, trachea, bronchi, and alveoli.
Gastrointestinal system: Consists of the mouth, stomach, small intestine, and large intestine.
Urogenital system: Includes kidneys, ureters, bladder, and urethra.
Musculoskeletal system: Bones and muscles.
Integumentary system: Comprises skin and associated structures.

Organs and Tissues

Organs are made up of multiple tissues.
Major tissue types include nervous, muscular, connective, and epithelial tissues.

Cells

Basic living units of the body; approximately 35-40 trillion in an adult.
Types of cells include nerve cells, muscle cells, connective tissue cells, and epithelial cells.

Composition of the Human Body

Average adult male body composition:
- Water: 60%
- Proteins: 20%
- Fat: 15%
- Minerals: 5%
- Carbohydrates: Minimal

Body Water Distribution

Total body water constitutes 60%:
- Extracellular Fluid (ECF): 20%
- Intracellular Fluid (ICF): 40%
- Intravascular Fluid (plasma): 5%

Normal Variations in Body Water

Infants and children: Approximately 75% of body weight.
Elderly: About 45%.
Females: Roughly 50%, due to higher fat content.
Obese individuals: Lower relative body water.

Dehydration Risks

Children experience rapid and severe dehydration due to higher ECF ratios.

Ion Distribution in ICF and ECF

Key cations:
- ICF: Potassium (K+) 140 mEq/L
- ECF: Sodium (Na+) 140 mEq/L
Key anions:
- ICF: Phosphate and proteins
- ECF: Chloride (Cl-) and bicarbonate (HCO3-)

Tonicity and Ionic Composition

Tonicity between ICF and ECF remains similar.
ECF consists of Interstitial Fluid (ISF) and plasma, with plasma containing more proteins.

Summary

The human body is structured as a complex organization of cells, tissues, organs, and systems, with water distribution being a critical aspect of composition and function.

Description

Explore the basics of human physiology, including its definition, organization of the human body, and composition. Learn about the different systems, organs, tissues, and cells that make up the human body.

Human Physiology Introduction

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Questions and Answers

What is human physiology concerned with studying?

What is the basic living unit of the human body?

Which of the following is NOT a system of the human body?

What is the function of the cardiovascular system?

Which tissue type is NOT mentioned in the text?

How many trillion cells are estimated to be in the human body?

What is the function of the gastrointestinal system?

Which of the following organs is NOT part of the urinary system?

What is the primary reason why total body water is lower in females?

What is the fraction of extracellular fluid (ECF) in the total body water?

Which ion has a concentration of approximately 140 mEq/L in the intracellular fluid (ICF)?

Which component has the higher concentration in plasma compared to interstitial fluid (ISF)?

What is the main anion in the extracellular fluid (ECF)?

What percentage of the typical adult male body is composed of fat?

Why do infants and children have a higher risk of rapid dehydration?

Which is true about the tonicity between ICF and ECF?