Chapter 46 - Muskoskeletal Flashcards
Changes in movement occur because muscles pull against a support structure, called the
Skeletal System
Three types of skeletal systems
- Hydrostatic skeletons
- Exoskeletons
- Endoskeletons
These skeletons are found primarily in soft-bodied invertebrates, both terrestrial and aquatic
Hydrostatic Skeletons
Locomotion in earthworms
Hydrostatic Skeletons
Description of how earthworms move using their hydrostatic skeletons
- Fluid-filled central cavity and surrounding circular & longitudinal muscles
- A wave of circular followed by longitudinal muscle contractions move fluid down body
- Produces forward movement
Locomotion in aquatic invertebrates
Hydroskeletons
Hydroskeletons occur in which two animal species?
- Aquatic invertebrates
2. Earthworms
Jellyfish produces regular _________ in bell
Pulsations
Description of movement in the hydrostatic skeletons in aquatic invertebrates
- Produce pulsations in bell
- Water moves under bell
- Squeezes some of water thrusts it forward
Description of movement of squids
- Hydrostatic Skeleton
- Fills mantle cavity with sea water
- Muscular contractions expel water forcefully through the siphon, and the animal shoots backward
Name of a squids locomotion
Jetting through their hydrostatic skeletons
Surrounds the body as a rigid hard case
Exoskeleton
What are exoskeletons made out of?
Carbohydrate Chitin
Two jobs of exoskeleton
- Protection for internal organs
2. Site for muscle attachment
Two limiting conditions of exoskeletons
- Must be periodically shed for body growth
2. Limits body size
Rigid internal skeletons that form the body’s framework and offer surfaces for muscle attachment
Endoskeleton
Echinoderms endoskeletons are made of _____
Calcite
Calcite is made out of
Calcium Carbonate
Echinoderms endoskeletons form ______ or ________
- Solid test
or - A network of spicules
The vertebrate endoskeleton is divided into _____
- Axial skeleton
2. Appendicular Skeleton
- Supports the body and protects internal organs
- Axis of the body
Axial Skeleton
- Limb bones and girdles
- Pectoral girdle and forelimbs
- Pelvic girdle and hindlimbs
Appendicular skeleton
Two components of the appendicular skeleton
- Pectoral girdle and forlimbs
2. Pelvic girdle and hindlimbs
Vertebrate endoskeletons have _________
- Cartilage
2. Bone
Bone and cartilage are living tissues which means ______
They can change and remodel in response to injury or physical stress
Bone and cartilage are _____
Connective Tissue
Connective Tissue is made up of ________
Fibroblasts
Make protein fibers within bone/cartilage matrix
Fibroblasts
Flexible, but resilient connective tissue
Cartilage
Cartilage is made up of ____ and ___
- Matrix of fibers
2. Chondroitin
Two types of cells that contribute to the production of cartilage
- Chondroblasts
2. Chondrocytes
Make new cartilage
Chondroblasts
Maintain existing cartilage
Chondrocytes
Hard but resilient connective tissue that is unique to vertebrates
Bone
Cell types that contribute to bone production
- Osteoblasts
- Osteocytes
- Osteoclasts
Make new bone
Osteoblasts
Maintains existing bone
Osteocytes
Breaks down existing bone
Osteoclasts
Bone develops in two ways:
- straight from mesenchyme
2. from a previously established cartilage model.
___________ initiate bone development
Osteoblasts
Osteoblasts change into ______ which resides in within the __________
- Osteocytes
2. Bone matrix
_______ break down the bone matrix
Osteoclasts
A protective layer, the _________ lines the outside of a bone.
Periosteum
Based on density, bone falls into these three categories
- Compact Bone
- SPongy Bone
- Vascular Bone
- Bone layer
- Outer dense layer
- Internal organization termed the Haversian system
Compact Bone
Another name for the compact bone
Haversian System
- Bone layer
- Honeycomb structure
- Forms the epiphyses inside a thick shell of compact bone
Spongy Bone
Mammals Bones
Vascular Bone
- Bone layer
- retain internal blood vessels
Vascular Bone
Bone structure in birds and fishes
- Avascular
2. Acellular
Mechanical stress in bones deforms bone crystals
Bone Remodeling
The phenomenon of remodeling
consists of two processes
- Small forces may not have a great effect
2. But larger forces can initiate remodeling by osteoblasts
Are the locations where one bone meets another
Joints
Three different kinds of joints
- Synarthritic
- Amphiarthritic
- Diarthritic:
immovable joints
Synarthritic
sightly movable joints
Amphiarthritic
freely movable joints
Diarthritic
Skeletal muscle fibers are attached to the periosteum of bones in one of two ways
- Directly
2. Through a strong, fibrous cord called the tendon
- In skeletal muscle movement
- Remains stationary during contraction
Origin
- In skeletal muscle movement
- is attached to a bone that moves when muscle contracts
Insertion
Muscle group causing an action
Agonist
Muscle group that counters movement
Antagonist
The force of contraction remains relatively constant as the muscle shorten in length
Isotonic contraction
The length of the muscle does not change as force is exerted
Isometric contraction
Each skeletal muscle contains numerous cells called ______
Fibers
Fibers are organized into bundles called ___________-
Fascicles
Each fiber encloses a bundle of organelles called ________
Myofibrils
Each myofibril in turn is composed of thick and thin _______
Myofilaments
Set of myofibrils are arranged in parallel known as _______
Sarcomeres
Stacked thick & thin myofilaments
Sarcomeres
Each sarcomere
- Consists of thin and thick myofilaments
2. The boundary consists of two Z lines
A muscle contracts and shortens because ________
The myofibrils contract and shorten
consists of a motor neuron and all of the muscle fibers it innervates
Motor Unit
In a motor unit
All fibers contract together when the motor neuron produces impulses
The cumulative increase in the number of motor units stimulated, leading to a stronger contraction
Recruitment
Types of muscle fibers
- Twitch
- Summation
- Tetanus
A muscle stimulated with a single impulse quickly contracts and relaxes
Twitch
is a cumulative response when a second twitch “piggy-backs” on the first
Summation
no relaxation between twitches; sustained contraction is produced
Tetanus
Locomotion in large animals involves:
- Appendicular locomotion
2. Axial locomotion
Produced by appendages that oscillate
Appendicular locomotion
Produced by bodies that undulate, pulse or undergo peristaltic waves
Axial Locomotion
Locomotion must deal with physical constraints to movement
- gravity
2. frictional drag
All aquatic vertebrates swim
that involves
Swimming involves using the body or its appendages to push against the water
Water buoyancy _______
reduces effect of gravity
Terrestrial locomotion deals mainly with
Gravity
Examples of locomotion on land
- Mollusks glide along a path of mucus
- Vertebrates and arthropods have a raised body, and move forward by pushing against the ground with jointed appendages
Flight has evolved among animals four times
- Insects
- Pterosaurs
- Birds
- Bats
Is achieved by pushing down against the air with wings
Propulsion
Insects, Pterosaurs, Birds, and Bats all have ___________
Lightened bones and forelimbs transformed into wings
