Systems Cells Homeostasis

Systems, Cells, and Homeostasis

Levels of Organization in the Human Body

• Cell: Basic unit of life.

• Tissue: A group of specialized cells of the same type that perform a common function.

• Organ: Two or more types of tissues working together to perform particular or specialized functions.

• Organ System: Many different organs that work together to carry out body functions.

• Multicellular Organism: Composed of various organ systems working together to sustain life.

Structural Organization of the Body

• Human Being Organism

• Cardiovascular System

  • Organ Systems

    • Heart (organ)

      • Tissues

        • Heart muscle (muscle tissue)

          • Cells

            • Muscle cell

              • Chemicals

                • Protein (actin)

The Different Organ Systems

• Hair

• Thymus

• Cartilage

• Nasal Passage

• Skeletal System

• Integumentary System

• Lymphatic System

  • Lymph nodes

  • Spleen

• Respiratory System

  • Lungs

• Bones

• Joints

• Nervous System

  • Brain

  • Spinal Cord

• Muscular System

• Digestive System

  • Stomach, small and large intestine, mouth, esophagus, liver, pancreas, gall bladder

• Urinary System / Excretory System

• Cardiovascular System

• Endocrine System

  • Hypothalamus, pituitary, thyroid, other glands

• Reproductive System

  • Testes, penis, associated ducts and glands

  • Ovaries, uterus, vagina, fallopian tubes, breasts

The 11 Organ Systems

1. Skeletal System

   • Components: Bones, cartilage, ligaments, tendons

   • Functions: Support and protection, movement, production of blood cells

2. Integumentary System

   • Components: Skin, hair, nails, sweat and oil glands

   • Functions: Protection, regulation of body temperature

3. Lymphatic / Immune System

   • Components: White blood cells, thymus, spleen

   • Functions: Defense against disease, production of white blood cells

4. Respiratory System

   • Components: Lungs, nose, nasal cavity, pharynx, trachea

   • Functions: Supplies oxygen to cells, removes carbon dioxide

5. Nervous System

   • Components: Brain, spinal cord, nerves

   • Functions: Regulates body’s response to changes in the internal and external environments

6. Muscular System

   • Types: Skeletal, smooth, and cardiac muscle

   • Functions: Voluntary and involuntary movement

7. Digestive System

   • Components: Stomach, small and large intestine, mouth, esophagus, liver, pancreas, gall bladder

   • Functions: Breaks down food, absorbs nutrients, eliminates waste

8. Urinary / Excretory System

   • Components: Kidneys, urinary bladder, skin

   • Functions: Filters blood, eliminates waste products, maintains homeostasis

9. Cardiovascular System

   • Components: Heart, blood vessels, blood, lymphatic vessels

   • Functions: Transports oxygen and nutrients, regulates body temperature

10. Endocrine System

    • Components: Hypothalamus, pituitary, thyroid, other glands

    • Functions: Produces hormones for maintaining homeostasis

11. Reproductive System

    • Components: Testes, penis, ducts, glands, ovaries, uterus, vagina, fallopian tubes, breasts

    • Functions: Production of sperm and ovum, secondary sex characteristics, sexual reproduction, environment for embryonic development

Various Types of Tissues

• Connective Tissue

• Muscle Tissue

• Nervous Tissue

• Epithelial Tissue

Direction Message Travels in Neurons

1. Nucleus

2. Soma

3. Axon terminals (cell body)

4. Dendrites

5. Axon

6. Myelin Sheaths

Muscular Components

• Fasciculi

• Endomysium (between muscle fibers)

• Nuclei

• Epimysium (fascia)

• Capillary

• Perimysium

• Skeletal Muscle Fibers

• Sarcoplasmic Reticulum

• Transverse (T) Tubule

• Sarcolemma

• Myofibrils

• Mitochondrion

• Sarcomere

• Striations

• Actin Myofilament

• Myosin Myofilament

• Cross-bridge

The Cell

• Basic unit of life.

  • All living organisms are made up of cells.

  • New cells arise only from pre-existing cells.

  • Smallest unit of life that can reproduce, grow, respond to stimuli, remain homeostatic, utilize materials from the environment, and adapt to the environment.

Cell Types

Prokaryotic Cells

• Structure: Nucleoid, no true nucleus, no membrane-enclosed organelles, typical cell wall, no cytoskeleton, single circular chromosome, binary fission, sexual reproduction via conjugation.

Eukaryotic Cells

• Structure: True nucleus, nucleoli, membrane-enclosed organelles, simple cell wall if present, cytoskeleton, linear chromosomes with histones, mitosis, sexual reproduction via meiosis.

Prokaryotic vs Eukaryotic Cells

• Animal Cell: Contains nucleus, nucleolus, mitochondrion, cytoskeleton, ribosomes, Golgi apparatus, centrioles, etc.

• Prokaryotic Cell Structure: Nucleoid apparatus, capsule, cell wall, cytoplasmic membrane, plasmids, flagella, etc.

Subcellular Components

• Plasma Membrane: Regulates entry and exit of substances.

• Nucleus: Contains genetic material (DNA).

• Cytoplasm: Semifluid matrix containing organelles.

• Organelles: Well-defined subcellular structures.

Nucleus & Nuclear Membrane

• Function: Stores genetic information in DNA.

• DNA + Proteins: Form chromatin, which coils into visible chromosomes during cell division.

• Nucleolus: Site of ribosome and rRNA production.

• Nuclear Envelope: Double-membraned, with nuclear pores.

Endoplasmic Reticulum (ER)

• Structure: A membranous system of sacs and channels.

  • Rough ER: Ribosomes attached; site of protein synthesis for export.

  • Smooth ER: No ribosomes; site of phospholipid synthesis and toxin breakdown.

Ribosomes

• Structure: Organelle composed of proteins and rRNA.

• Function: Site of protein synthesis, found in ER and free in cytoplasm.

Golgi Apparatus

• Structure: Stack of slightly curved saccules.

• Function: Involved in processing, packaging, and secretion of proteins and lipids.

Lysosomes

• Structure: Sacs produced by the Golgi Apparatus.

• Function: Contain hydrolytic enzymes for digestion, involved in autodigestion to recycle organelles.