Connective and Muscle Tissue Overview

Connective Tissue and Skin

• Connective tissue attaches to the deep surface of the skin and has a role in hair movement, resulting in goosebumps.
• Superficial fascia contains a high amount of fat that allows for movement of the skin over underlying structures.
• Certain areas of the body, such as palms, lips, and genitals, are hairless.

Muscle Tissue

• Functions of muscle tissue include movement generation, body form maintenance, and heat production.
• Types of muscle tissue:
  • Skeletal Muscle: Voluntarily controlled, striated, attached to bones, and produces movement at joints.
  • Cardiac Muscle: Specialized striated muscle making up the heart, controls contractions autonomously through its own conducting system.
  • Smooth Muscle: Non-striated, involuntarily controlled; found in organ walls, responsible for peristalsis in the GI tract and regulating blood vessel diameter.

Skeletal Muscle Characteristics

• Each skeletal muscle has an origin (least movable attachment) and insertion (most movable attachment).
• Muscle fibers are organized parallel to each other for coordinated contractions.
• Innervated by the somatic nervous system for conscious control.

Cardiac Muscle Characteristics

• Striated but involuntary, controlled by the autonomic nervous system.
• Characterized by its specific conducting system allowing involuntary rhythmic contraction.

Types of Skeletal Muscles

• Based on Shape:
  • Flat (e.g., external oblique)
  • Pennate (e.g., deltoid)
  • Fusiform (e.g., biceps brachii)
  • Quadrate (e.g., pronator quadratus)
  • Circular (e.g., orbicularis oris)

Functions of Bones

• Bones are a specialized form of connective tissue providing support and protection.
• Calcification of the extracellular matrix gives bones their hardness.
• Bones are living tissues composed of cells and fibers and maintain elasticity due to organic fibers.

Joint Classifications

• Joints are the articulations between two or more bones, allowing various movements and stability.
• Types of synovial (true) joints based on shape:
  • Plane Joints: Allow gliding movements, e.g., intercarpal joints.
  • Hinge Joints: Allow flexion and extension, e.g., elbow, knee.
  • Pivot Joints: Allow rotation, e.g., atlanto-axial joint.
  • Condyloid Joints: Allow flexion/extension and abduction/adduction, e.g., metacarpophalangeal joint.
  • Ball and Socket Joints: Allow multi-directional movement, e.g., shoulder and hip joints.

Stability of Joints

• Joint stability is influenced by:
  • The shape of the articular surfaces.
  • The presence of ligaments that stabilize joints (fibrous and elastic).
• Stable joints include the hip and ankle, while unstable joints include the knee and acromioclavicular joint.

Solid Joints (False Joints)

• Solid joints are connections between skeletal elements linked by fibrous connective tissue or cartilage.
• Includes fibrous joints (e.g., skull sutures) and syndesmoses.

Special Senses and Organ Systems

• The skull houses special senses such as smell, vision, taste, and hearing.

• Digestive and respiratory systems begin in the head and neck region, leading to various organs.### Anatomy of the Skull and Related Structures

• Pterygomaxillary Fissure: Connects to the pterygopalatine fossa.

• Temporal Fossa:

  • Bounded by the temporal line and zygomatic arch.
  • Pterion: Located 3-4 cm above the midpoint of the zygomatic arch; formed by the sutures of frontal, parietal, temporal, and sphenoid bones.
  • Clinically significant due to its thin structure, which can lead to bleeding if the middle meningeal artery is damaged.

• Occipital Bone:

  • External Occipital Protuberance (Inion): Palpable elevation serving as a muscle attachment.
  • Contains superior and inferior nuchal lines.
  • Lambda: Intersection of sagittal and lambdoid sutures.

• Critical Openings:

  • Foramen Magnum: Large opening in the occipital bone for the spinal cord and vertebral arteries.
  • Mastoid Process: Located on the temporal bone.
  • Styloid Process: Sharp projection beneath the acoustic opening.

• Fontanels:

  • Anterior Fontanel: Formed by sagittal and coronal sutures; closes around 18 months, becomes bregma.
  • Posterior Fontanel: Formed by lambdoid and sagittal sutures; closes around the first year, becomes the lambda.

Skull Base Anatomy

• Hard Palate: Composed of the palatine processes of the maxillae and horizontal plates of the palatine bone.

• Sphenoid Bone:

  • Irregular unpaired bone with body, greater and lesser wings, and pterygoid process.

• Foramen Magnum Functions:

  • Allows passage for the spinal cord, vertebral arteries, anterior and posterior spinal arteries, and the accessory nerve.

• Occipital Condyles: Provide articulation with the vertebral column.

• Jugular Foramen: Transmits the internal jugular vein and cranial nerves IX (glossopharyngeal) and XI (spinal accessory).

Superior Aspect of the Skull

• Shape: Oval, primarily formed by parietal bones.

• Bregma: Landmark at the intersection of sagittal and coronal sutures.

• Vertex: Highest point of the skull.

• Parietal Foramen: Located near the sagittal suture; allows for transmission of emissary veins.

Cranial Fossae

• Divisions: The internal surface is divided into three squamous fossa - anterior, middle, and posterior.

• Anterior Cranial Fossa:

  • Shallow, lodges frontal lobes.
  • Bordered by the inner frontal bone and lesser wing of the sphenoid.
  • Contains the optic canal (for CN II) and cribriform plate (for olfactory nerves).

• Middle Cranial Fossa:

  • Houses the temporal lobes; contains the most cranial openings.
  • Bounded by the lesser wing of the sphenoid and superior borders of the temporal bones.

• Posterior Cranial Fossa:

  • Deepest fossa, contains cerebellum, pons, and medulla oblongata.
  • Bordered by the petrous part of the temporal bone and squamous part of the occipital bone.
  • Key openings include the foramen magnum and jugular foramen (for cranial nerves IX, X, XI).

Scalp Structure

• Composition: Skin and subcutaneous tissue, covering the calvaria from the superior nuchal lines on the occipital bone to the supraorbital margins on the frontal bone.

This quiz covers the fundamental aspects of connective tissue and muscle tissue, including their roles, types, and characteristics. Learn how connective tissue supports skin structure and the distinct functions of skeletal, cardiac, and smooth muscle. Test your knowledge on these vital components of the human body.