A&P Lecture Exam 2

Intramembranous Ossification

flat skull bones form between sheets of primitive connective tissue

Endochrondral Ossification

Long bones and most of skeleton form from hyaline cartilage models

Steps of Endochrondral Ossification

Hyaline cartilage model

chondrocytes enlarge, lacunae grow

matrix breaks down, chondrocytes die

osteoblasts invade area and deposit bone matrix

osteoblasts form spongy then compact bone

once encased by matrix, osteoblasts are now osteocytes

zones of cartilage

resting

proliferating

hypertrophic

calcified

zone of resting cartilage

closest to end of epiphysis

resting cells; anchor epiphyseal plate to epiphysis

zone of proliferating cartilage

rows of young cells undergoing mitosis

zone of hypertrophic cartilage

rows of older cells left behind when new cells appear

thicken epiphyseal plate, lengthening the bone

matrix calcifies, chondrocytes die

zone of calcified cartilage

dead cartilage cells and calcified matrix

Functional properties of Hyaline Cartilage

most abundant, support with flexability and resilience

Functional properties of Elastic Cartilage

more stretchy fibers, able to stand repeat bending.

Functional properties of Fibrocartilage

great tensile strength. Rows of chondrocytes alternating with thick collagen fibers.

location of hyaline cartilage

articular (covers bone ends), costal (connects ribs), respiratory, and nasal

fetal skeleton

location of elastic cartilage

Only found in external ear and epiglottis.

location of fibrocartilage

Found in knee cartilage and vertibrae discs.

functions of bones

support, protection, movement

framework

blood cell formation

inorganic salt storage

functional importance of bone markings

holes for blood vessels and nerves to run through

depressions and protrusions to fit together

components of bone and their function

inorganic salts-hardness and compression resistance

organic components- cells, osteoid, collagen flexibility and tensile strength of bone

Compact bone location and texture

dense, outer layer that appears smooth and solid

Spongy bone location and texture

internal to compact bone, honeycomb needle-like, flat pieces called trabeculae

Location of Hematopoietic Tissue in Bones

Red bone marrow in trabecular cavities of spongy bone in long bones and diploe of flat bones

in long bones -Medullary cavities and all areas of spongy bone in infants

proximal epiphyses of humerus and femur in adults

homeostatic imbalances if composition of bone is not correct

osteoporosis (adults) rickets (children)

How does human growth hormone regulate bone growth?

regulates epiphyseal plate activity

too much- gigantisism

too little- dwarfism

How does thyroid hormone regulate bone growth?

ensures proper proportions of organic to inorganic materials

How do sex hormone regulate bone growth?

promote growth spurts and end growth by sealing epiphyseal plates

When does bone remodeling occur?

All the time, fractures, due to stress

role of parathyroid hormone in bone remodeling

regulating calcium-phosphate metabolism and its production increases in response to low serum calcium levels

role of calcitonin in bone remodeling

inhibits (blocks) the activity of osteoclasts

How does bone remodel in response to mechanical stress?

bones widen-matrix deposited under periosteum thickens bones

How are fractures classified?

position of bone ends

completeness of break

whether the bone penetrates the skin

Types of fractures

greenstick-kids, incomplete break, bone bends and ends fray

fissure- vertical, incomplete break

comminuted- fragments

transverse- right angle

spiral- around, due to twisting

oblique- at an angle

Treatments for fracture repair

reduction and immobilization

steps of fracture repair

hematoma

cartilaginous callus

bony callus

remodeling

Major parts of axial skeleton

Cranium, facial bones, vertebral column, thoracic cage

Major parts of appendicular skeleton

pectoral girdle, upper limbs, pelvic girdle, lower limbs

Functions of skull bones

protect brain, framework of head

Functions of facial bones

attachments for muscles that move face, holes for facial nerves

Bones of skull

frontal, parietal, temporal, occipital, sphenoid, ethmoid

facial bones

maxilla, palatine, zygomatic, lacrimal, nasal, mandible

bone marking of frontal bone and function

supraorbital foramen-channel for nerves and blood vessels

sutures of canium

coronal(frontal-parietal), saggital(parietal-parietal), squamous(parietal-temporal), lamboid(parietal-occipital)

Bone markings of temporal bones and function

external auditory meatus (tunnel to external ear)

mandibular fossa (depression for mandible attachment)

mastoid process (attachment site for certain muscles)

styloid process (movement of tongue)

zygomatic process (forms zygomatic arch)

jugular foramen (hole for jugular to pass through)

carotid canal (hold or carotid to pass through)

Bone markings of occipital bone and functions

foramen magnum (hole for spinal cord to pass throguh)

occipital condyles (articulation of atlas)

external occipital protuberance (attachment for muscles)

posterior cranial fossa (where the cerebellum sits in skull)

bone marking and functon of sphenoid bone

sella turcia (where pituitary gland sits)

Bone markings and functions of ethmoid bone

cribriform plate (allow passage of olfactory nerves)

crista galli (attachment for membranes surrounding brain)

perpendicular plate (form septum of nose)

Bone markings of maxilla bones and function

palatine process (forms hard palate)

alveolar process (cavities for teeth)

frontal process (forms lateral boundary of nose)

bone markings of zygomatic bones and functions

temporal process (forms zygomatic arch)

zygomatic arch (prominences of cheeks)

nasal bones

forms bridge of nose

hyoid bone

inferior to mandible, does not articulate with any other bone, provides base for tongue

divisions of vertebral column

7 cervical

12 throacic

5 lumbar

5 fused vertebrae of sacrum

coccyx

function of curvature of spine

increase resiliency and flexibility of spine

normal curvature of spine

cervical, throacic, lumbar, sacral

abnormal curvatures of spine

scoliosis(lateral curve), kyphosis(hunchback), lordosis (phatty)

Composition and function of intervertebral discs

fibrocartilage, shock absorber

herniated disc

disc slips out of place

cervical vertebrae

smallest, bifid spinous process, transverse foramen

C1

atlas, no body

C2

axis, dens

throacic vertebrae

rib facets on each side; inferiorly pointing spinous process

lumbar vertebrae

largest body; short, thick pedicles

sacrum

forms posterior wall of pelvis, 5 fused vertebrae

parts and landmarks of sternum

manubrium, body, xiphoid process, sternal angle (marks articulation of rib 2) jugular notch

manubrium

articulates with clavicles and first two pairs of ribs

body of sternum

articulates with ribs 2-7

xiphoid process

inferior end of sternum

ribs

1-7 true, 8-10 false, 11-12 floating

pectoral girdle

clavicle, and scapula; no direct articulation to axial skeleton; very light, high degree of mobility

pelvic girdle

sacrum and a pair of cocae (ischium, ilium, pubis)

attaches lower limbs to axial skeleton

Bones of Lower limbs

femur (head, neck, lateral and medial condyles)

patella

tibia (lateral and medial condyles, tibial tuberostity, medial malleolus

fibula (lateral malleolus)

tarsals (talus calcaneus)

metatarsals

phalanges

Bones of Upper limbs

Humerus (head, deltoid tuberosity, capitulum (radius) trochlea (ulna))

radius (head, styloid process)

ulna (trochlear notch, radial tuberosity)

carpals

metacarpals

phalanges

Functions of nervous system

gathering sensory input from sensory receptors

integration- processing and interpreting sensory input and deciding appropriate response

using motor output to activate effector organs (muscles and glands) to cause a response

Divisions of nervous system

CNS (brain and spinal cord)

PNS (peripheral nerves)

Function of CNS

integrating and control center

Functions of PNS

outside CNS receive sensory information and conduct motor information

Sensory (afferent) division of PNS

carries impulses toward CNS from sensory receptors

Types of sensory fibers

somatic -skin, voluntary movements

visceral-organs involuntary movements

Motor (efferent) division of PNS

carries impulses from CNS to effector organs

neuroglia of CNS

astrocytes- connects neurons to blood vessels

microglial cells-phagocytic cells

ependymal cells-line central canal; regulate CSF

oligodendrocytes- creates myelin sheath over neuron axons

neuroglia of PNS

satellite cells-support nuerons

Schwann cells - myelin sheath over neuron axons

function of dendrites

receive information

function of axons

conduct impulses to effectors or other neurons

Axon terminals

secrete neurotransmitters that either excite or inhibit other neurons

Functional classifications of neurons

sensory, motor, interneurons

Voltage

a measure of the amount of difference in electrical charge between two points

Current

the flow of electrical charge from point to point;

is dependent on voltage and resistance

Chemically gated channels

open in response to presence of chemicals

voltage gated channels

open in response to voltage changes

mechanically gated channels

open in response to vibration or pressure

Resting membrane potential

-70mV

Threshold membrane potential

-55mV

Resting potential concentration

higher Na+ concentration outside cell

higher K+ concentration inside cell

Depolarizations

inside of cell becomes less negative

hyperpolarizations

inside of cell becomes more negative than resting

repolarization

membrane potential returns to normal

graded potentials

short lived, local changes in membrane potentials;

EPSP and IPSP

graded potentials that occur in response to a neurotransmitter released from another neuron

Action Potential

occur in axons, interneuron communication; long-distance signals

Generation of Action Potential

increase in Na+ permeability into cell, restoration of Na+ impermeability, then short-lived increase in K+ permeability

Propagation of AP

local currents of an area undergoing depolarization causes depolarization of forward adjacent area

Conduction Velocity

Thicker axons conduct faster

myelinated axons conduct faster (saltatory conduction)

Synapse

junction that mediates information transfer between neurons or between a neuron or effector cell