Unit 1 lecture Exam: tissues, bones, joints and nervous system

What tissues are encountered in gross dissection?

Skin (epidermis + Dermis); Fascia (superficial + Deep)

Superficial Fascia

aka subcutaneous or hypodermis; loose connective tissue including fat; allows movement of skin; conduit for vessels and nerves; energy (fat) reservoir

Deep Fascia

dense, organized connective tissue; continuous with periosteum; surround muscles and groups of vessels/nerves; divides into compartments

What is the function of fascia?

support; protection; separation; transfer of forces

axial vs appendicular skeleton

Axial = skull, vertebrae, ribs, sacrum, coccyx; Appendicular = limbs, including pelvic and shoulder girdle

Long Bones

shaft/diaphysis and epiphyses with ends covered in articular cartilage; sustain body weight; form lever system for movement; Examples: metacarpals, femur, tibia, humerus, radius, ulna

Short Bones

length, width and height about equal in size; thin, compact bone surrounding cancellous bone; Examples: carpals, tarsals

Flat Bones

2 thin flat plates of compact bone surrounding cancellous bone; functions for protection; Examples: ribs, scapulae, skull

Sesamoid Bones

small, round bones found in joints that are held in place by tendons; functions in joint lever systems; Example: patella, pisiform

Irregular Bones

wide variety of unusual shapes; functions are specific to location; Example: vertebrae, ear ossicles

General categories of classification for joints

Synovial joints - skeletal elements are separated by a cavity; Solid joints - no cavity. components held together by connective tissue

Two classification of Solid Joints

Fibrous; a. suture (in skull) b. gomphosis (in teeth) c. syndesmosis (interosseous membrane); Cartilaginous; a. Synchondrosis (growth plate in long bone) b. symphysis (pubic symphysis)

What are the components of a synovial joint?

articular cartilage (made of hyaline cartilage) - compressible, low friction, wear resistant; Capsule - fibrous membrane anchored to bones - continuation of periosteum - thickening from intrinsic ligaments; Synovial Membrane - excretes and absorbs synovial fluid - joint lubrication - nutrition for cartilage; bursae; a. communicating- connected to joint space b. non-communicating - lie outside joint space

What are the different classifications of synovial joints?

Condylar (ellipsoid); Bicondylar; Hinge; Plane; Ball-and-Socket; Saddle; Pivot

Condylar (ellipsoid) Joint

elongated concave surface matched with elongated convex surface; permit flexion/extension, abduction/adduction and limited circumduction; Ex: radiocarpal joint of wrist

Bicondylar Joint

2 sets of contact points; allow movement mostly in one plane plus limited rotation; Ex: knee joint

Hinge Joint

permit flexion and extension only (movement in only one plane); ex: humeroulnar joint at elbow

Plane joint

between 2 slightly convex or slightly concave surfaces; allow sliding or gliding movements; Ex: AC joint, intercarpal joints

Ball and socket joint

Spherical convex surface paired with cup-like concave socket; permit flexion/extension, adduction/abduction, circumduction and rotation; ex: shoulder and hip

Saddle Joint

a type of synovial joint that connects two bones that are shaped like saddles, with one side concave and the other convex; permits flexion/extension, abduction/adduction, circumduction; Ex: carpometacarpal joint of thumb

Pivot Joint

movement occurs in one plane around and axis; rotation; Ex: atlanto-axial joint

What are the structural divisions of nervous system?

Central nervous system (CNS)-brain and spinal cord; Peripheral Nervous System (PNS)- all nervous system outside of CNS including spinal nerves, cranial nerves, visceral nerves and enteric system

general flow of info through nervous system

PNS > CNS > PNS; input: receptors. Sensory neurons in PNS receive stimulii and carry info to CNS; AFFERENT= toward CNS; processing: brain and/or spinal cord (CNS) integrates and processes info; output: effectors including motor neurons in PNS transmit responses; EFFERENT= away from CNS

Neuron

A nerve cell; composed of: a. dendrites (carry info into cell body) b. cell body (soma) c. axon/ nerve fiber (carry signal out of cell body) d. axon terminals (end plate)

Multipolar Neuron

efferent; ex: PNS motor neuron

Pseudonipolar neurons

afferent; has 2 axons and no dendrites; ex: PNS sensory neuron

Nerve

a bundle of axons (nerve fibers) in PNS; contains connective tissue and blood vessels; the cell bodies for nerve fibers are in the CNS or ganglia outside of the CNS

Parts of CNS

brain; a. gray matter: contains nerve cell bodies b. white matter: contains nerve fibers (axons); spinal cord; located in spinal canal of vertebral column; assoiciated with peripheral nerves that carry sensory and motor info

Parts of PNS

Afferent pseudounipolar axons carry info toward CNS (sensory); Efferent multipolar axons carry info away from CNS (motor)

What are the function divisions of the PNS?

somatic; visceral

Somatic division of PNS

innervates skin and skeletal muscle; receives and responds to info from external environment; consists of nerves that: a. carry conscious sensations from peripheral regions to CNS; created dermatomes (area of skin supplied by a single spinal nerve or spinal cord segment); b. innervate involuntary muscles; create myotomes (area of skeletal muscle innervated by a single spinal nerve or spinal cord segment)

classifications of somatic system

Somatic Sensory Afferents / General Somatic Afferents (GSAs); carry info from periphery to CNS; Somatic Motor Efferents / General Somatic efferents (GSEs); carry info away from CNS to skeletal muscle (PNS)

Visceral division of PNS

innervates organ systems, smooth muscles and glands; receives and responds to info from internal environment

classifications of visceral system

Visceral sensory neurons carry info to CNS; General Visceral Afferent (GVAs); Visceral motor neurons; General Visceral Efferent fibers (GVEs); make up autonomic division of PNS; sympathetic and parasympathetic parts

Enteric division of visceral system

controls activity of the digestive tract, pancreas, and gallbladder

How many spinal nerves and vertebrae in cervical spine?

8 nerves; 7 vertebrae (eat breakfast at 7); C1-C7 nerves exit above the vertebrae of the same name; C8 exits between C7 and T1 vertebra

How many spinal nerves and vertebrae in thoracic spine?

12 nerves; 12 vertebra (eat lunch at 12); nerves exit below vertebra of same name

How many spinal nerves and vertebrae in lumbar spine

5 nerves; 5 vertebra (dinner at 5); nerves exit below vertebrae of same name

How many spinal nerves and vertebrae in sacral spine?

5 nerves; 5 vertebra; vertebrae fuse to form sacrum; nerves exit below vertebrae of same name

How many spinal nerves and vertebrae in coccygeal spine?

1 nerve; 4 vertebra; vertebra fuse to form coccyx

Length of spinal cord

embryo: fills column length; at birth: extends caudally to L2-L3; adult: extends caudally to L1-L2; spinal cord shortens as you age; Discrepency caused because vertebral column grows faster than spinal cord

Vertebrosegmental Discrepancy

there can be a difference between where a spinal nerve originates and where it exits vertebral column; difference increases causally; Example: S4 nerve originates at spinal cord segment of L4 vertebra

Spinal Nerve Components

Dorsal roots (sensory); cell bodies located in dorsal root ganglia; ventral roots; cell bodies located in CNS; nerve formed by segmented ventral and dorsal roots; nerve exits intervertebral foramen; Divides into dorsal and ventral primary rami; lateral cutaneous branch; anterior cutaneous branch

Somatic plexuses

made from anterior rami of spinal nerves; cervical (neck) C1-C4; brachial (upper limb) C5-T1; lumbar (distal thoracic region, abdomen, pelvis, lower limb) L1-L4; sacral (pelvis and lower limb) L4-S4