02.03.2025_Nutrition Physiology I.pptx

Nutrition & Physiology I

• Instructor: Dr. Margaret Slavin, PhD, RDN

• Associate Professor, Nutrition & Food Science

• University of Maryland, College Park

Announcements

• Discussions are starting this week!

Agenda

1. Parts of the cell

2. Cell organization into tissues and organs

3. Organization into organ systems of the body

The Cell: The Basic Unit of Life

• Peroxisome: Destroys toxic materials.

• Golgi Complex: Packages proteins for export from the cell.

• Cell Membrane:

  • Lipid bilayer surrounding the cytoplasm

  • Regulates transport of substances in and out of the cell

• Endoplasmic Reticulum (ER):

  • Involvement in protein and lipid synthesis

  • Rough ER: Covered in ribosomes

  • Smooth ER: Lacks ribosomes

• Nucleus: Houses genetic material (DNA).

• Cytoplasm: Fluid and organelles within the cell.

• Mitochondrion: Main site of energy production.

• Ribosomes: Sites of protein synthesis.

• Lysosome: Digests worn-out or damaged components.

Types of Cells

• Loose Connective Tissue: Contains fibroblasts.

• Bone Tissue: Contains osteocytes.

• Specialized Cell Types:

  • Striated muscle cells

  • Nerve cells

  • Intestinal epithelial cells

  • Red blood cells

  • Smooth muscle

  • Fat (adipose) cells

Estimation of Cell Count

• Estimated number of cells in an adult human body: 37 trillion (Bianconi et al., 2012).

Cell Nucleus

• Functions:

  • Control center of the cell

  • Sends directions for cell growth, maturation, division, or death

  • Contains DNA, the genetic blueprint

• Genes: Segments of DNA that code for specific proteins, determining cell function.

Cell Membrane Components

• Carbohydrate Chains:

  • Function in cell identification and communication.

• Extracellular Fluid: Contains various proteins for structural support and function.

• Cholesterol: Provides structural support.

• Phospholipids: Form lipid bilayer, with hydrophilic heads and hydrophobic tails to regulate cell transport.

Cytoplasm

• Fluid and organelles located between the nucleus and the cell membrane.

Mitochondria

• Function: Powerhouse of the cell, providing ATP.

• Contains its own genetic material separate from nuclear DNA.

Endoplasmic Reticulum (ER)

• Role:

  • Membranous channels involved in synthesis, modification, and transport of cellular materials

  • Works closely with Golgi apparatus and ribosomes.

Ribosomes

• Function: Process genetic instructions to create proteins; can be free-floating or bound to the ER.

Golgi Apparatus

• Function: Packaging center for molecules processed by the ER for transport out of the cell.

Lysosomes

• Functions:

  • Housekeeping and recycling center

  • Digests foreign bacteria, rid of toxic substances, and recycles worn-out cell parts.

Body Organization

1. Cells

2. Tissues

• Groups of cells performing specialized functions.

• Types: Epithelial, Connective, Muscular, Nervous

3. Organs

• Groups of tissues performing specialized functions (e.g., brain, heart, liver).

4. Organ Systems

• Composed of multiple organs.

5. Organism

Integumentary System

• Components: Skin, hair, nails, sweat glands

• Functions:

  • Covering for the body

  • Maintains body temperature

  • Excretes salts and urea through perspiration

  • Vital for homeostasis.

Cardiovascular System

• Components: Heart, blood vessels, blood

• Function: Transports nutrients and oxygen throughout the body.

Blood Circulation Process

• Right Atrium: Receives deoxygenated blood from the body, especially from the liver and small intestine.

• Right Ventricle: Pumps deoxygenated blood to the lungs.

• Left Atrium: Receives oxygenated blood from the lungs.

• Left Ventricle: Pumps oxygenated blood to the entire body.

• Hepatic Portal Vein: Carries nutrient-rich blood from the GI tract to the liver.

Respiratory System

• Components: Lungs and respiratory passages (pharynx, larynx, trachea, bronchi)

• Functions: Takes in oxygen and excretes carbon dioxide, with nutrients affecting oxygen transport and mechanisms of protection.

Gas Exchange in Tissues

• In body tissues, red blood cells release oxygen and absorb carbon dioxide.

• In lungs, red blood cells absorb oxygen from air sacs and expel carbon dioxide.

Lymphatic System

• Components: Lymph vessels, lymph nodes, spleen, tonsils

• Functions: Returns fluids to blood, involved in lipid absorption, and important for defense against pathogens.

Fluids in the Body

• Plasma: Fluid in the blood

• Extracellular Fluid: Fluid outside of cells

• Intracellular Fluid: Fluid inside cells

• Lymph: Moves from bloodstream into tissue spaces, then travels through lymphatic vessels.

Skeletal & Muscular Systems

• Components: Bones, joints, ligaments, cartilage

• Functions: Provides support and protection, enables movement.

Nervous System

• Central Nervous System: Comprises brain and spinal cord, acting as the main control system.

• Peripheral Nervous System: Nerves and nerve cell clusters that relay information to the brain and are involved in sensation and interpretation.

The Nervous System & Hunger

• Key components involved: Hypothalamus, pituitary gland, spinal cord, cortex.

Endocrine System

• Components: Hypothalamus and various glands (pituitary, thyroid, adrenal, pancreas, etc.)

• Functions: Secretes hormones to regulate body activities like growth and reproduction.

Digestive & Urinary Systems

• Digestive System: Includes mouth, esophagus, stomach, intestines; functions to take in, break down, and absorb food, then excrete waste.

• Urinary System: Comprises kidneys, bladder, and ducts for the excretion of waste as urine, regulation of body water, salt balance, and acid-base balance.

Reproductive System

• Components: Gonads, genitals

• Function: Related to offspring production; certain nutrients essential for development and function.

Immune System

• Performing both nonspecific (innate) and specific (adaptive) defenses.

• Main cells: Lymphocytes and phagocytes

• Functions: Produce antibodies, destroy invader cells and viruses, clean up cellular debris, and help resist disease; nutritional status vital for immune response.

Conclusions

• For optimal health, all body systems must develop and function correctly.

• Systems interconnect to sustain life, and dietary habits significantly affect these systems.