#4: Locomotion Homeostasis & Ecology Flashcards
Animals movement dependent upon:
(most) Contractile proteins: actin & myosin
Types of movement
- Amoebic: amebas, WBCs
- Ciliary & flagellar: ciliates, epithelial surfaces (dep on proteins-tubulin & dynein
- muscular: muscles of all animals exert same force/X-sectional area
Cilia & flagella
- project from cell
2. 9 pairs of microtubules. surround a central pair: 9+2 (universal for all cilia/flagella in animal kingdom)
Pseudopodia
Extensions of cell cytoplasm, means fake foot
Sarcomere
- functional unit of muscle fiber
- holds Actin & myosin filaments
- filaments linked by molecular cross bridges that slide to shorten the sarcomere wh/ contracts the muscle
Control of Muscle Contraction
- W/out stimulation, fiber does not contract due to presence of TROPOMYOSIN
- Tropomyosin blocks binding sites on Actin where Myosin attach.
- Upon stimulation , Ca++ ions bind to Troponin, pull it away as Tropomyosin. Now myosin can bind to Actin (ATP is required); sliding can begin–> contraction
Neuromuscular junction
- where muscle fiber joins motor nerve
- When motor nerve is stimulated, Ach releases, acts on fiber & releases Ca++ ions (stored in sarcoplasmic reticulum)
3 types of muscle
- skeletal
- smooth
- cardiac
Skeletal
- Striated due to alternating myosin and actin proteins
- Many nuclei
- Fibers tied together by connective tissue
- Under voluntary control
Smooth
- Unstriated
- single nuclei
- organized as sheets
- found in walls of blood vessels, and around hollow organs
- under INVOLUNTARY CONTROL
Cardiac
- found only in heart
- one or two nuclei
- under involuntary control
ATP sources for muscle contraction
- Glucose: both transported to muscle via blood and derived from glycogen stored in muscle
- Creatine phosphate
Def. of Oxidative fibers
Muscles wh/ rely on aerobic metabolism of glucose for ATP
Def. of Glycolytic fibers
muscles wh/ rely on anaerobic metabolism of glucose (glycolysis) for ATP
Glycolytic fibers
- fast (bec use glycolysis)
- fatigue quickly (bec of lactic acid accumulation)
- don’t need extensive blood supply (appear white)
- used for short bursts of heavy exertion
Oxidative fibers
- slow (bec use aerobic metabolism)
- Don’t fatigue easily
- require extensive blood supply; get additional O2 via myoglobin
- appear red
- Used for slow, sustained activities.
Fast oxidative fibers
have best of both worlds
Homeostasis (tendency toward internal stabilization)
- recognized by Claude Bernard
- Metabolism depletes supplies/ produces wastes
- Influenced by external environment
- Reproductive system: only system not part of homeostatic mechanism of body
Set point
Point at which all other body systems function in an integrated manner to maintain the internal environment around (homeostasis)
Negative feedback regulation
Any deviations from set point that activate physiologic mechanisms to return environment to its set point
Animals living in open sea
- some do not experience large changes in salinity (stenohaline).
- Are in osmotic equilibrium w/ their environment
- Body fluid concentration changes with changes in seawater concentration
- Osmotic conformers
Animals living near coasts
- some have to tolerate large changes in salinity (euryhaline)
- Body fluid concentration remains steady even with concentration changes in surrounding water.
- Osmoregulators
Freshwater organisms
Need to excrete water/conserve salt