Biology Chapter on Homeostasis and Stem Cells

Organization of the Body

• The body is organized at different levels, starting with chemical level, cellular level, tissue level, organ level, and organ system level.
• Atoms are the smallest unit of matter. Essential atoms for life include carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, and sulfur.
• Molecules are two or more atoms joined together. Examples are DNA and glucose.
• Cells are the basic structural and functional units of an organism. Different types of cells include muscle, nerve, and epithelial cells.
• Tissues are groups of similar cells in structure and function. Primary tissues include epithelial, connective, muscle, and nerve tissue.
• Organs are combinations of different tissues that form a structural and functional unit. Examples of vital organs are the heart, liver, lungs, and brain.
• Organ systems are groups of organs that cooperate to perform major activities of the body. Examples of organ systems include the nervous system, integumentary system, muscular system, skeletal system and circulatory system, excretory system, digestive system, respiratory system, endocrine system and reproductive system.

Objectives

• Students should be able to understand the organization of the body, including cells, tissues, organs, and organ systems.
• Students should be able to identify different organ systems like integumentary, nervous, excitatory, reproductive, skeletal, muscular, and endocrine systems.
• Students should be able to locate cranial cavity, vertebral canal and other cavities.
• Students should be able to understand directional terms, planes, and sections of the body.
• The slides list additional objectives related to basic life processes, homeostasis, feedback regulation, body fluid compartments, and interstitial fluid.

Chemical Level

• Atoms are the smallest units of matter, crucial to life's functions. The essential elements for life include carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, and sulfur.
• Molecules, formed from atoms, such as DNA and glucose, are essential components in living organisms.

Cellular Level

• Molecules combine to form cells—the basic building blocks of life.
• Cells are the structural and functional units within an organism.
• Numerous cell types like muscle cells, nerve cells, and epithelial cells make up the human body.

Tissues

• Tissues are groups of similar cells with a shared structure and function.
• Adult vertebrates have four primary tissues: epithelial, connective, muscle, and nerve tissues.
• These tissues work together to accomplish various bodily functions.

Organs

• Organs are combinations of different tissues forming a structural and functional unit.
• A vital organ is one crucial for sustaining life, such as the heart (pumps blood), liver (removes toxins), lungs (supply oxygen), and brain (control center).

Cranial Cavity and Vertebral Canal

• The cranial cavity is formed by the cranial bones, protecting the brain.
• The vertebral canal is formed by the bones of the vertebral column and contains the spinal cord.
• Meninges are protective tissue layers lining the cranial cavity and vertebral canal.

Thoracic Cavity

• Also known as the chest cavity.
• Formed by ribs, chest muscles, sternum, and the thoracic portion of the vertebral column.
• Contains the pleural cavity (surrounds the lungs) and the pericardial cavity (surrounds the heart).

Abdominopelvic Cavity

• Extends from the diaphragm to the groin.
• Encircled by abdominal wall muscles and pelvic bones.
• Divided into abdominal (stomach, spleen, liver, intestines) and pelvic (urinary bladder, reproductive organs) cavities

Other Cavities

• Oral cavity: Mouth, containing the tongue and teeth.
• Nasal cavity: The nose.
• Orbital cavities: Contain the eyeballs.
• Middle ear cavities: Contain the small bones of the middle ear.
• Synovial cavities: Found within joints.

Methods of dividing the abdominal cavity

• The abdominopelvic cavity can be divided into quadrants (RUQ, LUQ, RLQ, LLQ) or regions (epigastric, umbilical, hypogastric, hypochondriac, lumbar, iliac).

Directional Terms

• Superior/Inferior (Cephalic/Caudal): Up/down relative to the body's midline.
• Anterior/Posterior (Ventral/Dorsal): Front/back relative to the body's midline.
• Medial/Lateral: Towards/away from the body's midline.
• Intermediate: Between two structures.
• Ipsilateral/Contralateral: Same/opposite side.
• Proximal/Distal: Nearer to/farther from the point of attachment.
• Superficial/Deep: Closer to/farther from the body's surface.
• Common directional terms include anterior, posterior, superior, inferior, proximal, distal, lateral, and medial.

Planes and Sections

• Sagittal plane: Divides the body into right and left sides. - Midsagittal plane: Divides the body into equal right and left sides. - Parasagittal plane: Divides the body into unequal right and left sides. - Frontal (coronal) plane: Divides the body into anterior and posterior portions. - Transverse (horizontal) plane: Divides the body into superior and inferior portions. - Oblique plane: Passes through the body at an angle.

Combining Forms

• Combining forms are prefixes or suffixes used to build medical terms.

Exercise Questions

• These questions cover various aspects of the content.
• They require identifying organ systems, cavities, and directional terms for correct answers.

Basic Life Processes

• Metabolism: The sum of all biochemical processes in cells, tissues, organs, and organ systems. (Includes Catabolism – breakdown of complex chemicals – and Anabolism –building up of simple chemicals)
• Responsiveness: The ability to detect and respond to changes in the internal or external environment.
• Movement: Intracellular, cellular, or organ motion (e.g., leg muscles moving the body).
• Growth: Overall increase in size due to cellular increase or size of cells.
• Differentiation: Development of specialized cells from unspecialized cells (e.g., stem cells).
• Reproduction: Formation of new cells (growth, repair, replacement) or of a new organism.

Homeostasis

• Homeostasis is the body's maintenance of a stable internal environment.
• This is regulated by the nervous and endocrine systems to counteract disruptions.
• It involves feedback systems—negative feedback (reverses a change) and positive feedback (reinforces a change)—maintaining balance in blood pressure, temperature, pH, etc.
• Homeostatic imbalances can lead to illness and death.

Compartments for Body Fluids

• Intracellular fluid (ICF) is inside cells.
• Extracellular fluid (ECF) is outside of cells, including interstitial fluid within tissues and plasma in blood vessels.

Interstitial Fluid and Body Function

• The regulation of interstitial fluid is vital to cellular function.
• The composition of the fluid changes as it moves to transport nutrients (glucose, oxygen, ions) and remove waste (carbon dioxide) from tissues throughout the body.

Homeostatic Imbalances

• Disruptions of homeostasis lead to conditions or illnesses.
• A disorder is a general term for any abnormality or change in function.
• A disease is a disorder with recognizable symptoms and signs.
• Local diseases affect a small area; systemic diseases affect the entire body.
• Signs (observable) and symptoms (felt) help clinicians diagnose and treat ailments.

Homeostatic Mechanisms

• Includes mechanisms for detecting changes from normal conditions and initiating corrective actions.
• Three major components:
  • Receptor: Detects changes, sends input to the control center.
  • Control center (integrating center): Analyzes input, generates an output signal (e.g., hormonal or nerve impulse).
  • Effector: Receives output commands and produces a response to counteract the change.
• Feedback (negative or positive) systems continually adjust physiological parameters.