Types of Sweat Glands

Apocrine Sweat Glands

• Made of dense, keratinized cells
• Become active at puberty
• Secrete sticky, cloudy sweat into hair follicles in armpits, around nipples, and in the pubic region
• Sweat is a food source for bacteria on skin, increasing odor

Merocrine Sweat Glands

• Also called eccrine sweat glands
• Very numerous with high numbers on soles and palms
• Coiled tubular structure secretes watery perspiration directly onto surface of skin
• Sweat also contains electrolytes, urea, and organic nutrients
• Sodium chloride gives it a salty taste

Repair of the Integument

• Skin regeneration occurs because stem cells of epithelium and connective tissue undergo cell division
• Replacing lost or damaged tissue
• Time depends on extent of damage
• Four steps of skin repair:
  • Scab formation
  • Tissue granulation
  • Scab removal

Bones of the Inner Ear

• Located inside the petrous part of the temporal bone
• Three smallest bones of the body: Malleus, Incus, and Stapes (smallest bone in the body)
• These bones articulate with each other and transfer vibrations from the tympanic membrane to the inner ear

Laryngeal Skeleton

• Also known as the larynx or voice box
• Composed of nine cartilages
• Located between the trachea and the root of the tongue
• The hyoid bone provides an anchor point
• The laryngeal skeleton both opens and closes the glottis and regulates the degree of tension of the vocal folds, which produce vocal sounds when air is forced through them

Bones of the Vertebral Column

• The vertebral column is a flexible column formed by a series of 24 vertebrae, plus the sacrum and coccyx
• Commonly referred to as the spine
• Extends from the base of the skull to the pelvis
• Spinal joints do not have a wide range of movement, but they still allow the spine great flexibility
• Two facet joints help to prevent slippage and torsion

The Thoracic Cage

• Formed by the ribs and sternum
• Protects internal organs and gives attachment to muscles involved in respiration and upper limb movement
• The sternum consists of the manubrium, body of the sternum, and xiphoid process
• Ribs 1-7 are called true ribs because they articulate directly to the sternum
• Ribs 8-12 are known as false ribs

Joints in the Human Body

• Joints hold the skeleton together and support movement
• Types of joints:
  • Immoveable joints
  • Joints that allow a slight movement
  • Joints allowing full movement

Muscle Tissue

• There are three main types of muscle tissue:
  • Skeletal (striated or voluntary)
  • Smooth
  • Cardiac
• Skeletal muscle tissue is composed of long cells with a striated appearance
• Skeletal muscles attach to and move bones by contracting and relaxing in response to voluntary messages from the nervous system

Skeletal Muscle

• The typical male body contains approximately 640 muscles, which compose around two-fifths of its weight
• The same number in a female body make up a slightly smaller proportion
• Muscle fibers are organized into bundles supplied by blood vessels and innervated by motor neurons

Special Movements

• Dorsiflexion – lifting the foot
• Plantar flexion – depressing the foot
• Inversion – turn foot inward
• Eversion – turn foot outward
• Supination – hand facing upward
• Pronation – hand facing downward
• Opposition – touching thumb to other fingers

Types of Muscles

• Prime mover – muscle with the major responsibility for a certain movement
• Antagonist – muscle that opposes or reverses a prime mover
• Synergist – muscle that aids a prime mover in the same movement and helps prevent rotation or unwanted movement
• Fixator – stabilizes the origin of a prime mover so all tension can be used to move the insertion bone

Muscles of the Pelvis, Hip, and Thigh

• Muscles can lead to disorders of the muscular system

Muscles of the Lower Leg

• Carpal tunnel syndrome, also called median nerve compression, occurs when the tendons become inflamed, causing compression of the median nerve
• Symptoms include pain, numbness, and eventual weakness in the hand