Animal Biology Fundamentals: Cells, Tissues, and Systems
Animal Biology Fundamentals: Eukaryotic Cells
Nucleus: Holds genetic material. Protected by a double membrane that separates it from the cytoplasm.
Vacuoles: Small sacs that store various substances.
Lysosomes: Produced by the Golgi apparatus; responsible for digesting materials inside the cell.
SER (Smooth Endoplasmic Reticulum): Produces lipids and aids in detoxification (removal of toxic substances).
Mitochondria: Have two membranes; break down glucose to release energy via cellular respiration.
Cytoplasm: Jelly-like fluid containing the cytoskeleton, which provides support and shape to the cell.
RER (Rough Endoplasmic Reticulum): Stores and transports proteins synthesized by attached ribosomes.
Ribosomes: Smallest organelles, lacking a membrane; responsible for protein synthesis, found free or attached to the RER.
Cell Membrane: Made of lipids and proteins; protects the cell and controls what enters and leaves (selective permeability).
Golgi Apparatus: Modifies and packages substances from the RER, sending them outside the cell using vesicles.
Centrosome: Formed by two centrioles; separates chromosomes during cell division and forms cilia and flagella for movement.
Types of Animal Tissues
1. Connective Tissue
Made of cells that secrete substances forming the intercellular matrix, which separates them. This tissue supports, protects, and connects other tissues.
Connective Tissue Proper: Common type; surrounds and connects organs; features a gel-like matrix (e.g., tendons, ligaments).
Adipose Tissue: Stores fat in specialized cells called adipocytes for energy storage and protection.
Cartilaginous Tissue: Forms cartilage; characterized by an elastic and solid matrix; cells are called chondrocytes.
Blood Tissue: Features a liquid matrix (plasma) containing red and white blood cells and platelets; transports substances and provides bodily protection.
Bone Tissue Structure
Characterized by a hard matrix containing calcium phosphate, primarily for structural support. Osteocytes (bone cells) are found in small spaces called lacunae.
Compact Bone: The dense outer layer of bones.
Spongy Bone: The inner part containing holes filled with red bone marrow.
2. Muscle Tissue
Composed of fibers that contract to produce movement.
Smooth Muscle: Found in the walls of hollow organs (e.g., intestines, blood vessels); movement is involuntary.
Cardiac Muscle: Found exclusively in the heart; involuntary and highly resistant to fatigue.
Skeletal Muscle: Attached to bones; responsible for voluntary movement and maintaining posture.
3. Epithelial Tissue
Covers and lines body surfaces, forming a protective barrier.
Covering/Lining Epithelium: Covers the body and lines organs; structure varies depending on its specific function.
Glandular Epithelium: Forms exocrine glands (which excrete substances) and endocrine glands (which release hormones directly into the blood).
4. Nervous Tissue
Specialized for transmitting nerve impulses throughout the body.
Made of neurons (star-shaped cells responsible for transmission) and neuroglia (support and protect neurons).
Animal Organ Systems: Nutrition and Metabolism
Circulatory System: Transports substances throughout the body.
Organs: Heart, arteries, veins.
Digestive System: Responsible for supplying nutrients.
Organs: Mouth, tongue, teeth, stomach, intestines.
Respiratory System: Takes in oxygen and removes carbon dioxide.
Organs: Nostrils, lungs, bronchioles, trachea, larynx, pharynx.
Excretory System: Removes metabolic waste and maintains water and mineral balance.
Organs: Kidneys, bladder, urethra, ureters.
Organ Systems for Interaction and Reproduction
Reproductive System: Responsible for creating new life.
Female Organs: Ovaries, uterus, vagina, vulva, fallopian tubes.
Male Organs: Testicles, penis, urethra.
Nervous System: Receives and interprets stimuli, and sends corresponding messages.
Organs: Brain, nerves, sense organs.
Endocrine System: Produces and regulates hormones.
Organs: Hypothalamus; pituitary, thyroid, parathyroid glands; ovaries, testicles.
Locomotor System: Enables movement; provides structural support and protection.
Organs: Bones, muscles.
The Process of Acquired Immunity
The body’s specific defense mechanism against pathogens.
Antigens enter the body.
B-cells recognize the antigens and begin to multiply.
They differentiate into **plasma cells** that produce large amounts of **antibodies**.
Some **B-cells** become long-lasting **memory cells**.
Upon secondary exposure, the antigen enters the body again.
**Memory cells** quickly recognize the specific antigen.
The remaining **B-cells** activate much faster than during the initial exposure.
A significantly larger quantity of antibodies is produced rapidly.
The antigen is destroyed or blocked before illness can develop.
Separately, **T-cells** destroy infected or damaged body cells.