Review Aguilar pt2

• Functions of the skin

  • Covers the underlying tissues protecting them from dehydration, injury, and germ invasion
  • Regulates body temperature by controlling the size of the blood vessels in the dermal layer; cells in the dermal layer produces sweat that remove heat when it evaporates
  • Helps create vitamin D when exposed to ultraviolet light from the sun
  • Site for many nerve endings with different types of receptors (pain, heat, pressure, etc.)
  • Temporary storage for fat, glucose, water, salt
  • Reduce harmful radiation contained in sunlight
  • Absorbs drugs and other chemical substances
• Structures of the skin

  • Epidermis – the outermost layer; made of epithelial cells; no blood vessels present; forms the acidic/waterproof barrier; composed of several sublayers
  • Dermis – known as the "true skin"; made up of connective tissue; contains blood vessels, sweat glands, oil glands, hair follicles, nerve endings/receptors
  • Hypodermis – (subcutaneous tissue) – attaches the dermis to the muscle and is made of: areolar connective tissue which contains WBCs that destroy pathogens, adipose tissue which serves as a cushion and insulation from the cold
• ● Types of bone tissue 

  o Compact bone – solid bone made of osteons or haversian systems 

  ▪ Osteon – cylindrical tubes that contain osteocytes and spiderlike tunnels called canaliculi; the opening of the osteon is called a haversian canal 

  ▪ Haversian canals – contain nerves and blood vessels 

  o spongy bone – has visible cavities and resembles a sponge; the cavities contain red bone marrow which produce RBCs and 5 types of WBCs 

  o Periosteum – made of fibrous connective tissue; covers the bone; fibers merge with those of tendons
• Epidermis sublayers

  • Stratum germinativum (basal) – the base layer where skin cells reproduce (new cells)
  • Melanocytes – found right above the basal layer; produce a pigment called melanin which gives skin its color; melanocytes are stimulated by sunlight
  • Stratum corneum – outermost epidermal layer; consist of dead cells filled with keratin
• Glands

  • sebaceous glands – open to the skin surface; produce sebum (oil); protect skin from drying out and from colonization of bacteria
  • ceruminous glands – located in the ear canals; produce cerumen (wax); keeps eardrum flexible and prevents drying
  • sweat glands – made mostly of water and very small amounts of hundreds of other chemicals; the slight variations give each person their own scent; there are two types of sweat glands: apocrine glands – located in the axillae and genital areas; sweat produced is odorless, however, bacteria produce waste that create unpleasant smell, eccrine – located all over body especially in forehead, upper lip, palms, and soles; important in maintaining body temperature by evaporating and removing large amounts of heat
• Burns

  • First degree – superficial; only affects the epidermis
  • Second degree – partial-thickness; affects the epidermis and dermis; blisters present; very painful
  • Third degree – full-thickness; affects the epidermis, dermis, and subcutaneous tissue; may also involve deeper tissues (muscle, bone); not painful; may be life-threatening
• Hair

  • root – part of hair implanted in the dermis
  • shaft – hair that projects from the skin
  • hair follicle – embedded in the epidermis
  • alopecia – loss of hair for different reasons (genetic, hormones, medication, age)
• Functions of the skeletal system

  • Supports body
  • Provides shape
  • Protects organs
  • Allows movement (levers)
  • Provides storage for minerals and salts
  • Produces blood (hemopoietic)
  • Is a site for homeostasis
• There are 206 bones in the body
• Classification of bones

  • Long bones – bones of arms, legs, fingers, feet (NOT wrist and ankles)
  • Short bones – bones of wrist and ankles
  • Irregular bones – vertebrae and facial bones
  • Flat bones – ribs, shoulder blades, pelvis, cranial bones
• Parts of long bones

  • Epiphysis – short end of a long bone
  • Diaphysis – long middle part of a long bone; also known as the shaft; contains the medullary cavity
• Medullary cavity

  Contains yellow bone marrow which is mostly adipose tissue
• Types of bone tissue

  • Compact bone – solid bone made of osteons or haversian systems
  • Spongy bone – has visible cavities and resembles a sponge; the cavities contain red bone marrow which produce RBCs and 5 types of WBCs
• Osteon


  Cylindrical tubes that contain osteocytes and spiderlike tunnels called canaliculi; the opening of the osteon is called a haversian canal
• Haversian canals

  Contain nerves and blood vessels
• Periosteum

  Made of fibrous connective tissue; covers the bone; fibers merge with those of tendons
• Ossification


  Cartilage skeleton that is replaced by bone; starts in the third month of pregnancy; bone growth and replacement continues through ages 18-21
• Fontanels


  Skull bones that have not yet been closed; permits the baby's head to compress during childbirth
• Epiphyseal line


  Chondrocytes located at the epiphyseal plate produce cartilage in the growing bones; when the last chondrocyte dies, the epiphyseal plate ossifies completely and becomes the epiphyseal line. This marks the end of growth (height).
• Bone remodeling


  Repair and maintenance of older bone in response to environmental and calcium changes
• Tendon


  Connects bone to muscle
• Ligament


  Connects bone to bone
• Types of fractures


  • Closed (simple) - broken bone but still in anatomical position (inside skin)
  • Open (compound) - broken bone has moved and pierced the skin
  • Greenstick - the bone contains collagen and splints rather than breaks; common in young children
  • Comminuted - two or more fractures creating fragments
  • Impacted - fractures caused by forcing one bone against another such as fractures to lower legs due to jumping from a high altitude
  • Pathologic - fractures due to disease such as osteoporosis
• Axial skeleton


  • Cranial/facial bones (occipital, frontal, zygomatic, maxillary, mandible, parietal, temporal, sphenoid, ethmoid, lacrimal, nasal, inferior nasal concha, vomer, palatine)
  • Rib cage (true/false/floating ribs, parts of the sternum – xiphoid process, manubrium, body)
  • Vertebrae (cervical (7), thoracic (12), lumbar (5), sacrum, coccyx), intervertebral discs
• Appendicular skeleton


  • Shoulder girdle (scapula, clavicle)
  • Humerus, ulna, radius
  • Carpals, metacarpals phalanges
  • Pelvic girdle (coxae, sacrum, ilium, pubis, ischium, pubic symphysis)
• Types of joints


  • Synarthrosis (fibrous) – immovable joints; sutures (between cranial bones and facial bones)
  • Amphiarthrosis (cartilaginous) – slightly movable joints; symphysis (between vertebrae and pubic bones)
  • Diarthrosis (synovial) - freely movable; Ball and socket (humerus and scapula; pelvic bone and femur), Hinge (humerus and ulna, femur and tibia, between phalanges), Condyloid (temporal and mandible), Pivot (atlas and axis, radius and ulna), Gliding or plane (between carpals; sacrum and ilium), Saddle (thumb)
• Muscle functions


  • Body movement
  • Provides body shape and form
  • Produces body heat and maintains body temperature
• Types of muscles


  • Smooth muscle - small tapered cells, no striations, one nucleus in each cell, involuntary contraction, found in viscera
  • Cardiac muscle - branched cells, faint striations, one nucleus in each cell, involuntary contraction, found in the heart only
  • Skeletal muscle - large cylindrical cells, striations, several nuclei in each cell, voluntary contraction, attached to bones
• Neuromuscular junction


  Axon terminal, sarcolemma, synaptic cleft, acetylcholine receptors, acetylcholine, cholinesterase
• Sarcolemma


  Electrical changes (resting potential, action potential)
• Major muscles


  • Head/neck (sternocleidomastoids, masseter)
  • Trunk (trapezius, rectus abdominis, pectoralis major, latissimus dorsi, diaphragm)
  • Shoulders/arm (deltoid, biceps brachii, triceps brachii, hand and finger flexors/extensors)
  • Hip and leg (gluteus maximus, gluteus medius, iliopsoas, quadricepts, hamstrings, gasctocnemius, tibialis anterior)
• Functions of the nervous system


  • Regulate the body by communicating with neurotransmitters
  • Detect changes and feel sensations
  • Initiate response to changes
  • Organize and store information
• Types of neurons


  • Sensory neurons (afferent) - carry impulses from the body to the brain
  • Motor neurons (efferent) - carry impulses from the brain to the body
  • Interneurons - connect one neuron to another
• Central nervous system


  • Brain - Brainstem (Medulla, Pons, Midbrain), Cerebellum, Hypothalamus, Thalamus, Cerebrum
  • Meninges - 3 layers enclose and protect the spine and brain: dura mater, arachnoid, pia matter
  • Cerebral spinal fluid - circulates through the brain's ventricles to the subarachnoid spaces and central canal of the spinal cord; brings nutrients to the CNS neurons and removes waste; also acts as a shock absorber (cushions the CNS)
  • Cranial nerves
  • Spinal cord - transmits impulses to and from the brain; integrates the spinal cord reflexes (ascending tracts, descending tracts, spinal nerves)
• Peripheral nervous system


  • Autonomic nervous system - Sympathetic division, Parasympathetic division
  • Visceral sensory, Visceral motor, Somatic sensory, Somatic motor
• Endocrine system


  Regulates body functions via hormones
• Posterior Pituitary


  • Stores hormones produced by the hypothalamus
• Antidiuretic hormone (ADH)


  Increases water reabsorption by kidney (decreases urine output)
• Oxytocin


  Stimulates contraction of the uterus and release of milk from the mammary glands
• Anterior Pituitary


  • Secretes hormones that stimulate other glands