Support, Protection, and Movement Ch 29 Flashcards
what is Integument and its functions?
Outer covering of the body
* Functions
– Protection against abrasion & bacteria
– Prevents fluid loss
– Protects from UV rays
– Temperature regulation
– Sensory
– Excretory (e.g., sweat)
– Respiration for some animals
– Absorb nutrients for some animals
Invertebrate Integument
- Unicellular animals = cell membrane
- Most Invertebrates – single layer epidermis
- Phylum Platyhelminthes (some flatworms)
– Syncytial tegument = multinucleate outer layer; no individual cells - Phylum Mollusca
– Mantle (tissue layer) secretes outer shell - Phylum Arthropoda
– Cuticle functions as exoskeleton
– Epidermis (hypodermis) secretes cuticle
Syncytial tegument
= multinucleate outer layer; no individual cells
Vertebrate Integument
- Epidermis (ectoderm derived); stratified squamous epithelium
– Cells contain Keratin (fibrous protein) - Keratinization causes cells to become cornified; form stratum corneum
– Chromatophores contain pigments (e.g. melanins) - Dermis (mesoderm derived); dense connective tissue layer
– Contains nerves, blood vessels, collagen fibers, fat cells, glands,
immune cells, etc.
– May contain dermal bone
Epidermis
The outer layer of the two main layers of the skin.
-(ectoderm derived); stratified squamous epithelium
-– Cells contain Keratin (fibrous protein)
* Keratinization causes cells to become cornified; form stratum corneum
– Chromatophores contain pigments (e.g. melanins)
Dermis
The inner layer of the two main layers of the skin. The dermis has connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures.
-(mesoderm derived); dense connective tissue layer
– Contains nerves, blood vessels, collagen fibers, fat cells, glands,
immune cells, etc.
– May contain dermal bone
in the epidermis Cells contain Keratin (_______ _________)
fibrous protein
Hydrostatic Skeletal
(sometimes just called “hydrostats”) use a cavity filled with water; the water is incompressible, so the organism can use it to apply force or change shape.
-Plants use osmotic pressure to pressurize the cavity, whereas animals do it with muscle layers in the hydrostat’s walls.
29.5 What are the two types of rigid skeletons?
- Exoskeleton e.g., cuticle, shell
- Endoskeleton – formed inside body
Notochord
a longitudinal flexible rod of cells that in the lowest chordates (such as a lancelet or a lamprey) and in the embryos of the higher vertebrates forms the supporting axis of the body
bone forms in what two ways? and how are they different?
– Endochondral bone
* Cartilage model is invaded by osteocytes
* Bone tissue replaces cartilage (ossifies)
– Intramembranous (dermal) bone
* Forms in dermis
* No cartilage precursor; osteocytes gather and form bone
Spongy vs. Compact Bone
- Spongy = framework of bony tissue in center of bone
- Compact = dense, solid outer bone; typically long bones
- Concentric rings form an ________; blood vessels in center
Osteon
What is a bone cell called?
osteocyte
What builds bone and what breaks it down/ resorbs bone?
Osteoblast = build bone; Osteoclast = resorb bone
Axial Skeleton
Skull, vertebral column, sternum & ribs
Appendicular Skeleton
Limbs (fins or wings)
Sliding Filament Hypothesis
- Dynein arms bind to tubulin subunit
- Bend to move tubulin subunit up
- Release and bind to subunit below
- Repeat rapidly; then reverse
- Result = bending of cilia or flagellum
What are the three types of movement?
Ameboid
Ciliary (tiny cilia) and Flagellar (long flagellum)
3. Muscular Movement
Ameboid movement
resembling an amoeba especially in moving or changing shape by means of the flow of cytoplasm
-(pseudopodia)
Outer layer of gel-like ectoplasm surrounds inner, more fluid, endoplasm
Hydrostatic pressure of endoplasm pushes against ectoplasm Involves interaction of actin and actin-binding proteins
Ciliary (tiny cilia) and Flagellar (long flagellum) movement
Cilia and Flagella have the same structure
Comprised of Microtubules composed of tubulin
Microtubules are arranged as 9 doublets in a peripheral circle + 1 central doublet
(9 + 2 arrangement = 9 doublets + 2 microtubules)
Anchored in cytoplasm by a basal body (Kinetosome); triplets
Microtubule-Associate Protein, MAP (Dynein) forms arms that bridge doublets
Flagellum
propel parallel long axis
(perpendicular to cell)
Cilia
propel perpendicular to long axis
(parallel to cell)
Cilia beat
in waves
Muscular Movement and what are the three types?
Three Types of Muscle
* Skeletal (striated)
– Multinucleate
– Attach to skeleton; movement
* Cardiac (striated)
– Uninucleate; branching cells
– Heart; involuntary control (myogenic)
* Smooth
– Uninucleate; lacks striations
– Typically around organs & glands
– Involuntary control (autonomic)
Invertebrates have smooth & striated
muscle; many variations
Striated muscle structure:
_________(pl. fascicles) = bundle of muscle fibers (1 fiber = 1 cell)
Each muscle fiber (cell) comprised of many _______
Myofibrils are ______ and_______ filaments
______ = functional unit; defined by Z-lines
Fasciculus
myofibrils
Actin and Myosin
Sarcomere
29.11 Describe how the sliding-filament hypothesis of muscle contraction works.
Step 1: Action potential; influx of Calcium
Active sites exposed
Step 2: Myosin binds; requires ATP to move head
Step 3: Myosin bends; pulls actin filaments closer
Step 4: Myosin releases
Step 5: Repeat until contraction is complete
Cross-bridge cycling; 50-100x/sec
Energy source is glucose (aerobic), glycogen
(aerobic & anaerobic), & creatine phosphate
Motor unit
motor neuron + muscle fibers; each terminal
branch of a neuron innervates one fiber
Muscle Fiber Types and Function
- Slow oxidative fibers (red muscles)
– High blood supply; aerobic; Lots mitochondria and myoglobin
– Slow, sustained contraction (e.g., posture) - Fast fibers
– Fast glycolytic fiber (white muscle; anaerobic); Burst of speed; requires rest
– Fast oxidative fiber (aerobic); High blood supply, lots mitochondria &
myoglobin - Rapid, sustained activities (e.g., migration; marathon running)
- Invertebrate muscle
– Have smooth, striated & oblique striated muscle (many variations)
