Chapter 49 Organization of the Body

I. Organization of the body:

A. Vertebrates share a common body plan

B. “Tube within a Tube”

1. digestive tract

2. coelom (internal body cavity suspending digestive tract)

C. 2 divisions

1. thoracic cavity:

a. pericardial cavity heart

b. pleural cavity lungs

2. peritoneal cavity

a. separated by diaphragm from thoracic

b. contains stomach, intestines, liver

D. Skeleton

1. jointed bones internal with cartilagenous blocks to allow growth

2. skull to protect brain

3. vertebrae to protect nerve cord/spinal cord.

E. heirarchy of organization

1. cells è tissues è organs è organ systems

2. ( atoms è molecules è cells è tissues è organs è organ systems è organism è population è community è ecosystem è biome è biosphere )

F. Tissues: groups of similar cells grouped/functioning

1. germs layers differentiate early and are: endodoerm, mesoderm, ectoderm

2. 4 principle tissues that develop are: epithelial, connective, muscle, nerve

G. organs: groups of tissues functioning together.

H. Organ systems: groups of organs functioning together to carry out a major body function.

II. epithelial tissue

A. covers/lines body surface:

1. skin: ectoderm epithlia

2. digestive tract: endoderm epithlia

3. pleural membrane: mesoderm epithelia

B. characteristics:

1. avascular

2. rapid regeneration time

3. secretion/absorption/protection/filatration

4. cellular

C. classified/named based upon #of cell layers & cell shape

1. membranous vs. glandular

2. # layers: simple vs. stratified (pseudostratified)

3. shape: squamous, cuboidal, columnar, transitional

a. simple squamous: alveoli of lungs, capillary lining,

b. simple cuboidal: small gland ducts

c. simple columnar: respiratory pathway, digestive pathway

i. can have cilia, microvilli, goblet cells

d. stratified squamous: skin

e. stratified cuboidal:

f. stratified columnar:

g. transitional:

h. pseudostratified: respiratory tract

D. exocrine vs. endocrine

1. exocrine have ducts è products onto body surface

2. endocrine have no ducts è products into blood

III. Connective tissue

A. connects and supports

1. connective tissue proper: loose or dense from mesoderm

2. special connective tissues: cartilage, bone, blood, adipose from mesoderm

B. Characteristics

1. vast extracellular matrix

2. vascular

C. classified/named

proper

1. dense regular connective: tendons, ligaments (collagen is organized)

2. dense irregular connective: capsule of kidney, periosteum, epimysium, perineurium.

Special

1. cartilage: ground substance of glycoprotein, non elastic, flexible, strong produced by chondrocytes in lacunae

2. bone: most are cartilage with a calcified matrix

a. ostein supplies osteocytes with blood/nutrients

b. central (haversian canal), canaliculi, perforating canal

3. blood: matrix is fluid plasma

a. cells are

i. erythrocytes: hemoglobin/oxyhemoglobin

j. leukocytes: neytrophils, eosinophils, basophils, lymphocytes, monocytes for immunity.

b. cells parts are thrombocytes/platelets

IV. muscle tissue:

A. contracts/shortens for movement

1. smooth: non striated, spindle shaped, involuntary

found: surrounding blood vessels, digestive tract, iris of eye

innervation: some require innervation some just regulated by nerves

2. cardiac: striated, intercalated discs (gap junctions- opening between adjacent cells), bifurcated, involuntary

found: in heart

innervation: regulated by nerves

3. skeletal: striated, syncitial (multinucleate), contain myofibrils of actin & myosin, voluntary

found: attached to bone

innervation: nerves from cerebral cortex and below

V. nerve tissue:

A. produces electrochemical signals for communication of body parts

1. neuron: conducts signal

2. neuroglia: associates with nuerons to assist neuronal communication

B. characteristics

1. neurons: sodium/potassium pump generates concentration gradient across cell membrane creating polarity (Na+ pumped out so membrane potential is –60mV inside)

2. neuroglial: some are wrapped around neurons as myelin sheath to insulate and speed signal.

C. system divisions

1. central nervous system

brain & spinal cord

2. peripheral nervous system

spinal annd cranial nerves, ganglia

D. functional divisions

1. somatic

a. voluntary

afferent: pain to brain

efferent: brain to muscle

b. involuntary

afferent: pressure receptor in viscera to brain

efferent: brain to diaphragm

2. autonomic

a. sympathetic: fight or flight

b. parasympathetic: revover from fight or flight