Animal Tissues Flashcards

Animal Tissues

• Chapter 41 focuses on animal tissues.

Types of Muscle Tissue

• Muscle tissue is the most abundant tissue type.
• Cells are specialized to contract, generating mechanical force.

1. Skeletal Muscle

• Usually attached to bone in vertebrates.
• Provides the force needed for locomotion.
• Under voluntary control.

2. Smooth Muscle

• Often surrounds hollow tubes, like bronchioles in lungs.
• Controls the tube's diameter.
• Smooth muscle contraction is involuntary.

3. Cardiac Muscle

• Found only in the heart.
• Muscle cells are interconnected.
• Provides the force needed for a heartbeat.
• Cardiac muscle contraction is involuntary.

Nervous Tissue

• Complex networks of neurons.
• A single nerve cell is a neuron.
• Initiate and conduct electrical signals from one part of the animal’s body to another.
• Electrical signals produced in one neuron may:
  • Stimulate or inhibit other neurons.
  • Initiate new action potentials in other neurons.
  • Stimulate muscle cells to contract.
  • Stimulate glandular cells to release chemicals.

Components of Nervous Tissue

• Neuron: The fundamental cell of the nervous system, responsible for transmitting electrical signals.
• Dendrite: Portion of the neuron that receives signals.
• Axon: Portion of the neuron that transmits signals.
• Synapse: Structure that permits a neuron to pass an electrical or chemical signal to another neuron.
• Microglia: A type of glial cell that acts as the primary immune defense in the central nervous system.
• Oligodendrocytes: A type of glial cell that produces myelin.
• Myelin Sheath: Insulating layer around nerves which increases the speed of electrical signals.
• Astrocytes: A type of glial cell that provides support and nutrition to neurons.

Epithelial Tissues

• Sheets of densely packed cells.
• Cover the body or enclose organs.
• Line the walls of body cavities.
• Tissue is asymmetrical or polarized.
  • Apical surface – exposed to fluid or air.
  • Basal lamina – extracellular matrix that separates it from underlying tissue.

Types of Epithelial Tissues

• Simple columnar epithelium (with goblet cells and brush border)
• Structure can vary in layers (one layer, multiple layers).
• Cell shape can vary (flat, elongated, cube).
• Multi-layered tissues can expand and contract.

Connective Tissues

• Connect, anchor, and support.
• Includes blood, adipose, bone, cartilage, loose and dense connective tissue.
• Form extracellular matrix (ECM) around cells.
  • Provides a scaffold for attachment.
  • Protects and cushions.
  • Provides mechanical strength.
  • Transmits information.

Types of Connective Tissues

• Loose connective tissue: Abundant throughout animals' bodies, holding internal organs in place and providing the internal framework of the body; composed of loosely arranged collagen fibers mixed with elastin.
• Dense connective tissue: As in tendons and ligaments, with tightly packed layers of collagen fibers in parallel arrays, giving the tissue great strength but very little flexibility.
• Adipose tissue: Composed of lipid-filled cells, providing a layer of protection and insulation around internal organs and under the skin; a major energy store.
• Blood: Composed of red and white blood cells and platelets suspended in a watery fluid called plasma, which is rich in electrolytes, proteins, and other solutes.
• Bone: Composed of bone-forming cells that secrete the protein collagen; the collagen is embedded in a hard casing composed of calcium and phosphorus, which gives bone the inflexible, tough characteristics for support and protection.
• Cartilage: Formed by collagen-secreting cells; not mineralized and is therefore softer and more flexible than bone, providing flexibility of movement and cushioning of joints.

Hierarchical Organization

• Living organisms are composed of organs, tissues, and cells.
• A tissue is a group of cells consisting of one or more cell types that together perform a specialized function.
  • Muscle, nervous, epithelial, and connective tissues.
• An organ consists of several types of tissues that together carry out particular functions.

Organs

• Composed of different types of tissues.
• Examples: Intestine, Stomach

Tissue Layers in Organs (e.g., Stomach)

1. Simple squamous epithelial tissue
2. Connective tissue
3. Nervous tissue
4. Layers of smooth muscle tissue

Organ Systems in Animals