Motor Systems: Support and Movement

Integumentary, Skeletal, and Muscular Systems

Chapters 31 and 39

I. Integumentary System

A. a body’s covering

• skin, skin glands, hair, nails, and associated structures

B. invertebrate skin

• secretion, protection, and/or gas exchange

C. vertebrate skin

1. complex tissue with several layers

a. epidermis, dermis, hypodermis

b. cutaneous vs. subcutaneous

2. generally no gas exchange function

3. protection, support, heat regulation, sense of touch

4. features

a. sweat and oil (sebaceous) glands

b. hair follicles and hair

c. sensory receptors and nerves

d. pigment cells (melanocytes)

e. small blood vessels (capillaries)

Fig. 31.7 Human skin anatomy

II. Vertebrate Tissues

A. nerve tissue – discuss later

B. muscle tissue – discuss later

C. epithelial tissue (epithelium)

1. linings and coverings

2. skin (epidermis and dermis)

3. glandular epithelium

4. classification types

a. simple vs. stratified vs. pseudostratified

b. squamous vs. cuboidal vs. columnar

c. any form can be ciliated

Fig. 31.1 Types of epithelial tissue in vertebrates

Fig. 31.1 Types of epithelial tissue in vertebrates

D. connective tissue

1. holds body together

2. bone, cartilage, ligaments, blood, tendons, fascia, fat (adipose)

3. connective tissue matrix

• collagen, fibroblasts, elastin

Fig. 31.2 Diagram of fibrous connective tissue

Fig. 31.3 Types of connective tissue in vertebrates

Fig. 31.3 Types of connective tissue in vertebrates

III. Invertebrate Support and Movement

A. hydrostatic skeleton (“soft skeleton”)

1. pressure generated by body fluids

• fluids press against inside of body wall

2. base for muscle action

B. exoskeleton (“cuticle”)

1. hard skeleton lying outside soft body parts

a. chitin

b. does not grow with org.; must be shed

2. four functions:

a. base for muscle action

b. movement of joints

c. prevents water loss

d. protects soft body parts

3. muscle organization

a. origin vs. insertion

b. occur in pairs (antagonists)

Fig. 39.13 Antagonistic muscles

C. endoskeleton

1. hard skeleton that lies within body grows with organism

2. muscles also occur as antagonists

3. echinoderms and vertebrates

IV. Vertebrate Endoskeletons

A. cartilage skeletons

1. clear, relatively soft substance

• chondrocytes embedded in protein matrix

2. cartilage is the forerunner to bone

B. bone skeletons

1. five functions:

a. supports body

b. attachment site for muscles

c. protection of internal organs

d. some produce blood cells (red, white, and platelets)

e. natural reservoir of Ca

2. bone is a living tissue composed of several parts

a. periosteum

b. spongy bone

• red marrow produces the various blood cells

c. compact bone

i. yellow marrow within the medullary cavity

ii. Haversian systems (osteons)

iii. osteocytes

d. ends of bones are capped with cartilage allows joints to function

Fig. 39.4 Anatomy of a long bone

3. organized into axial and appendicular divisions

a. skull, vertebrae, pelvic girdle, pectoral girdle, limbs

b. joints can be immovable or movable

• several different types of movable; some are synovial

Fig. 39.5 The human skeleton

V. Vertebrate Muscle

A. smooth

1. involuntary

2. cells are long and tapered; occur in sheets

3. single nucleus

4. examples

B. cardiac

1. involuntary; only in heart

2. rhythmic and tireless

3. single nucleus

4. cells are cylindrical, branching, and web-like

C. skeletal

1. voluntary; moves limbs, other muscles, or just itself

2. multinucleated and striated; unbranched

3. contractions tire over time

4. examples

Fig. 31.5 Muscular tissue

Fig. 39.12 Human musculature

VI. Structure of Skeletal Muscle

A. not all muscles move bones

B. tendons and fascia

C. whole muscle bundles of muscle fibers (fascicles)

• muscles fibers are long and surrounded by sarcolemma

o neuromuscular junctions

D. muscle fibers myofibrils actin and myosin myofilaments

E. myofilaments arranged into individual contractile units called sarcomeres

Fig. 39.14 Skeletal muscle fiber structure

VII. Muscle Contraction

A. sliding filament model

1. involves interaction between the myofilaments of each sarcomere

a. nerve impulses reach a neuromuscular junction

b. Ca+ ions are released and cause myosin to bind to actin

c. actin filaments slide past myosin filaments sarcomeres contract entire muscle contracts movement occurs

B. ATP is needed to supply energy for contraction

Fig. 39.14 Skeletal muscle fiber function