Connective and Muscle Tissues Overview

Connective Tissues

• Connective tissues provide support, structure, and insulation.
• Loose Connective Tissue (e.g., Areolar): Supports, offers elasticity, and facilitates nutrient diffusion.
• Dense Connective Tissue (e.g., Tendons, Ligaments): Strong, fibrous tissue crucial for tensile strength.
• Cartilage: Provides structural support in different forms:
  • Hyaline: Found in joints, reducing friction.
  • Elastic: Found in ear and epiglottis, offering flexibility.
  • Fibrocartilage: Located in intervertebral discs, absorbing shock.
• Bone: Provides structural support and protection, storing calcium.
• Adipose Tissue: Stores energy, insulates, and cushions organs.
• Blood: Transports nutrients, gases, hormones, and waste.

Muscle Tissue

• Muscle tissue enables movement and comes in three forms:
• Skeletal Muscle: Striated, multinucleated fibers; responsible for voluntary movement, attached to bones.
• Cardiac Muscle: Striated, branched fibers with intercalated discs; involuntary, pumps blood in the heart.
• Smooth Muscle: Non-striated, spindle-shaped fibers; involuntary, found in walls of hollow organs (intestines, blood vessels).

Sliding Filament Theory

• Explains muscle contraction at a molecular level.
• Key Components: Actin (thin filament), Myosin (thick filament), Troponin/Tropomyosin (regulatory proteins), ATP (energy source).
• Steps in Contraction:
  • Calcium release from sarcoplasmic reticulum.
  • Troponin activation (calcium binding triggers tropomyosin shift, exposing actin binding sites).
  • Cross-bridge formation (myosin heads bind to actin).
  • Power stroke (myosin head pivots, pulling actin).
  • ATP binding and detachment (ATP causes myosin release, resetting for another cycle).
  • Relaxation (calcium pumped back, muscle relaxes).

Nervous Tissue

• Nervous tissue specializes in communication and control.
• Neurons: Conduct electrical impulses;
  • Structure: Cell body (nucleus and organelles), Dendrites (receive signals), Axon (transmits signals).
• Neuroglia (Glial Cells): Support neurons and maintain the blood-brain barrier.
  • Types: Astrocytes (support neurons, blood-brain barrier), Microglia (immune cells), Oligodendrocytes (CNS myelin), Schwann cells (PNS myelin).

Muscle Fiber Types

• Fast Twitch (Type II):
  • Contracts quickly, high force, fatigue rapidly.
  • Anaerobic metabolism, less mitochondria and myoglobin.
  • Examples: Sprinting, weightlifting.
• Slow Twitch (Type I):
  • Contracts slowly, low force, resistant to fatigue.
  • Aerobic metabolism, high mitochondria and myoglobin.
  • Examples: Long-distance running, cycling.

Diagrams to Study

• Sarcomere structure
• Neuromuscular junction
• Fast and slow twitch fiber comparison
• Nervous tissue structure (neuron and glial cells)

This quiz explores the characteristics and functions of connective and muscle tissues. It covers various types of connective tissues, such as loose and dense connective tissue, as well as cartilage, bone, adipose tissue, and blood. Additionally, it details the three forms of muscle tissue, including skeletal, cardiac, and smooth muscle, vital for body movement and function.