Chapter 40 ~An Introduction to Animal Structure and Function I. Tissues: groups of cells with a common structure and function (4 types)

Chapter 40 ~An Introduction to Animal Structure and Function

• I. Tissues: groups of cells with a common structure and function (4 types)

• A. Connective tissue:

– 1. structure -

• a. most abundant & widely distributed

• b. Exists in more varied forms than any other tissue

• c. Form of connective tissue determined by matrix

–matrix is non-living material between cells

– 2. function –

• a. forms a supporting framework for body as a whole & individual organs

:

• 3. 3 types

– Collagen fibers (protein)– flexible

– Elastin fibers (protein) rubbery

– Reticular fibers (thin branched collagen fibers)

• 4. examples:– Blood – fluid matrix– Adipose – gel-like & sparse– Bone – most specialized– Cartilage & fibrous

• B- Epithelial tissue: – 1. structure

• a. held together by tight junctions (very little matrix)

• b. forms continous sheets that are avascular – Avascular = no blood vessels (gets materials

through osmosis– 2. function

• a. protective lining outside of body and protective lining of organs and cavities (includes mucus membrane)

• b. identified by shape

3. examples

a. Simple: single layer of cells

b. Stratified: multiple tiers of cells

c. Cuboidal (like dice)

d. Columnar (like bricks on end)

e. Squamous (like floor tiles)

• C.-Nervous tissue: senses stimuli and transmits signals from 1 part of the animal to another

– 1. Structure

• A. 3 types of nerve cells- sensory, motor, assoc.

– 2. function

• A. to receive, interpret, & respond to stimuli

• D- Muscle tissue: capable of contracting when stimulated by nerve impulses; myofibrils composed of proteins actin and myosin; 3 types:– 1. structure

• A. Large, long cells• B. 3 types

– 1) striated/skeletal– 2) smooth – organs, involuntary– 3) cardiac – heart

II. Organization• A. levels or organization:• Atom• Molecule• Cell• Tissue• Organ• System• Organism• (population, community)

• Circulatory-internal distribution• Digestive-food processing• Excretory-waste disposal;

osmoregulation• Endocrine-coordination of body

activities• Immune/Lymphatic-defense• Integumentary-protection• Muscular-movement; locomotion• Nervous-receive, interpret, responedto

stimuli• Respiratory-gas exchange• Reproductive-reproduction• Skeletal-support; protection

III. Internal regulation

• A. Interstitial fluid: internal fluid environment of vertebrates; exchanges nutrients and wastes

• B. Homeostasis: “steady state” or internal balance

• C. Negative feedback: – 1. change in a physiological variable that is

being monitored triggers a response that counteracts (negatively) the initial fluctuation; 2. ex. body temperature

• D. Positive feedback: – 1. physiological control mechanism in which a

change in some variable triggers mechanisms that amplify the change (positively)

– 2. ex.uterine contractions at childbirth

IV. Metabolism: sum of all energy-requiring biochemical reactions

• A. terms

– 1. Basal Metabolic Rate (BMR): minimal rate powering basic functions of life (endotherms)

– 2. Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)

• B. Thermoregulation- maintaining body temp

– 1. Endotherms aka homeotherms: bodies warmed by metabolic heat

• Body temp constant

– 2. Ectotherms: aka poikliotherms bodies warmed by environment

• Body temp changes with environment

– 3. regulation of body temp

• 3. regulation of body temp

– a. cooling by evaporation

• Sweating

– b. warming by metabolism

• Muscle contraction & other metabolic activities generate heat

– c. adjusting surface area to regulate temp

• Change vol of blood flow to extremities

• d. countercurrent exchange – (in cold environs) warm blood moving to extremities runs adjacent to cold blood moving away from extremities – heat absorbed by cold blood is redistributed to internal parts of body