Introduction to Animal Structure and Function

AP BiologyAP Biology

Levels of Structural Organization

Cells Tissues

Organs Organ Systems

Four Principle Tissue Types

Epithelial tissueEpithelial tissue—covers and protects the body surface, lines body cavities, specializes in moving substances into and out of the blood

Connective tissueConnective tissue—supports the body and its parts, to connect and hold them together, and to transport substances through the body

Four Principle Tissue Types

Muscle tissueMuscle tissue—produces movement; specialized for contractility

Nervous tissueNervous tissue—specialized in communication between various parts of the body and in integration of their activities

Epithelial Tissue

Sheets of tightly packed cells Cells held together by tight junctions Functions as a protective barrier

Dermis Cells Keratinocyte - (90%) anchoring junctions Melanocyte - melanin blocks UV light, shields nucleus Langerhans cell - Macrophage

Epidermal Layers Deep layer

single layer of stem cells & melanocytes division produces keratinocytes keratinocytes - anchoring junctions cells have keratin - dense "waterproof" protein nuclei break down

Top layer approx. 25 layers of flat dead cells filled with keratin continuously shed

Simple Squamous Epithelium

Simple Cuboidal Epithelium—alveoli

Stratified Squamous Epithelium—lining of the mouth

Simple Columnar Epithelium—lining digestive tract/organs

Pseudostratified Columnar Epithelium—lining trachea and bronchi

cilia

Transitional Epithelium—lining urinary passages and bladder; allows for distension and evacuation

Connective Tissue Made of 3 kinds of protein fibers:

Collagenous fibers—made of collagen; nonelastic and do not tear easily when pulled lengthwise

Connective Tissue Made of 3 kinds of protein fibers:

Collagenous fibers Elastic fibers—long threads of elastin; lends tissue

resilence Reticular fibers—thin, branched fibers composed

of collagen and continuous with collagenous fibers; aids in joining connective tissue to adjacent tissues

Extracellular Matrix—ground substance that is composed of a web of fibers embedded in a uniform foundation that may be liquid, jellylike, or solid

Loose Connective Tissue

Holds organs in place and attaches epithelia to underlying tissues

Two types of cells: Fibroblasts—

secrete proteins of the extracellular fibers

Macrophages—phagocytic amoeboid cells that function in immune defenses

Has all 3 fiber types

Adipose tissue

Loose connective tissue specialized to store fat

Insulates the body and stores fuel molecules Each adipose cells has one large fat droplet

which varies in size as fats are stored or used

Fibrous Connective Tissue

Dense arrangement of collagenous fibers in parallel bundles

Found in tendons (attach muscles to bone) and ligaments (attach bone to bone)

Cartilage

Composed of collagenous fibers embedded in chondroitin sulfate

Chondrocytes secrete collagen and chondroitin sulfate (makes cartilage strong and flexible)

Cartilage makes up skeleton of vertebrate embryo—most gets replaced by bone except ears, nose, trachea, invertebral discs and ends of some bones

Growth Plate

Bone

Mineralized connective tissue Osteoblasts—bone forming

cells deposit collagen and calcium phosphate matrix which hardens to form hydroxyapetite

Consists of repeating Haversian systems

Right image:

1. Haversian Canal

2. Canaliculi

3. Lamellae

4. Lacunae

Blood Liquid extracellular matrix of plasma that

contains water, salts, and proteins Blood cells made in red bone marrow near ends

of long bones Cellular components:

Erythrocytes— red blood cells; transport oxygen

Blood

Leukocytes—white blood cells; immune defense

neutrophilseosinophils

basophil

Blood

Platelets—cell fragments; blood clotting

Nervous Tissue

Senses stimuli and transmits signals from one part of the animal to another

Neuron—specialized to conduct an impulse or bioelectric signal

Consists of:Cell bodyDendrites—conduct impulses to cell bodyAxons—transmit signals away

Muscle Tissue

Long, excitable cells capable of contraction Cell cytoplasm contains bundles of

microfilaments made of the contractile proteins, actin and myosin

Most abundant tissue in the body 3 types: skeletal, cardiac, and smooth

Muscle Tissue Skeletal

Attached to bones by tendons

Microfilaments aligned to form a banded (striated) pattern

Voluntary muscle movements

Muscle Tissue

CardiacForms the contractile walls of the heartEnds of cells joined by intercalated disks,

which relay contractile impulse between cells

Muscle Tissue

SmoothFound in walls of internal organs (digestive

tract, bladder) and arteriesSpindle-shaped cells contract slowly, but can

retain contracted conditions longer than skeletal muscle

Involuntary movements

Energy InputIngestion

Digestion(Hydrolysis)

Absorption

Catabolism(Cellular Respiration)

Energy stored(ATP)

Energy lost(heat)

Energy used(ATP)

Bioenergetics

Heterotrophs harvest chemical energy from the food they ingest

Metabolism Metabolic rate—total amount of energy an

animal uses per unit of time; usually measured in calories or kilocalories

Determined by measuring:Amount of oxygen used for an animal’s

cellular respirationAn animal’s heat loss per unit of time

Endotherms—generate own heat metabolically Exotherms—acquire heat from environment

Homeostasis--Regulating internal environment Dynamic state of equilibrium in which internal

conditions remain relatively stable; steady state Depends on feedback circuits

Receptor detects internal changeControl center processes info and directs to

effector to respondEffector provides the response

Homeostasis--Regulating internal environment Positive feedback—

enhances initial change in variable and response of effector

Negative feedback—stops or reduces the intensity of the original stimulus

Negative feedback in a thermostatic control