Unit 4 Part 3 Flashcards
B3.3 - Muscle and motility
Motile organisms?
Organisms that have adaptations allowing movement within their habitat
Sessile organisms?
Organisms that can’t move from place to place
- Are able to alter their body form in response to environmental stimuli
Ex. of sessile organism?
Venus flytrap
- Dionaea muscipula
- In subtropical wetlands, N + S carolina
- Deficient in nitrogen
How does a Venus fly trap obtain nutrition and nitrogen?
Obtains nutrition through photosynthesis and nitrogen through its prey
Ex. of Motile organism?
Brown throated three toed sloth
- Bradypus variegatus
- Avg speed = 0.25 km/h-1
- are arboreal ( tree dwelling)
- Herbivorous
- Slow digestive ( month)
- Poop once a week
- Good swimmers
Muscle fibers?
Cells found in each muscle ( thousands)
- Multinucleate
Why are muscle fibers Multinucleate?
B/c each fibre represents several cells that have merged together
Myofibrils?
Protein filaments found in each muscle fiber that run parallel to each other
What are myofibrils placed along?
Contracting units called sarcomeres
What happens when one sarcomere contracts?
B/c they are all attached to all sarcomeres in same muscle contract
- Resulting action makes the muscle fiber and entire muscle shorter`
What proteins are in sarcomere?
Myosin and actin
How do muscles shorten when sarcomeres contract?
When they contract , the actin filaments slide over the myosin fibres which results in each sarcomere shortening
What is it called when muscles shorten due to sarcomere’s contacting?
The sliding filament theory
Rigor mortis
Condition where bodies become v rigid a few hours after death
How does rigor mortis happen?
The result of no new ATP being generated after death
Tendons?
Connective tissues used in muscles to attach two bones
Two types of bones in a muscle?
Origin and insertion
- Origin: Acts as an immovable anchor
- Insertion: Moves as a result of muscle contraction
Antagonistic muscles?
Muscles that accomplish opposite movements b/c a muscle can only exert a force when it contracts so when a bone is moved it needs another muscle
Titin?
An immense protein that has multiple folds that allow it to act as a spring
- It’s spring like action allows muscles to use a force to help w/ relaxation
What creates a spring like tension in titin
When a sarcomeres shorten during a contraction and two sides of each sarcomere move towards centre
- Released when muscle relaxes
Neuromuscular junctions?
Electrical impulses originating in your brain and terminating at synapses
What does every movement made require?
Many neuromuscular junctions
Motor neurons?
Neurons that carry messages from neuromuscular junctions
Synapses?
Locations where the electrical activity of a neuron is converted into a chemical release at the terminal end
What is the chemical released by synapses?
A neurotransmitter
What type of synapse are neuromuscular junctions?
Type of synapses where a chemical message is sent into the muscle tissue to stimulate a contraction
Each muscle is able to contract w/ varying intensity depending on..
How many of the total muscle fibers w/in the muscle receive a nervous system impulse to contract
Motor unit?
A set number of muscle fibers that each single motor neurons controls
How do motor units work?
If low intensity contraction is needed, a relatively low number of motor units is activated by the brain, vice versa
Ratio of motor neurons to muscle fibers?
Varies from about 1;10 to 1;200
What are vertebrate animals endoskeleton/ internal made out of?
Bones
- Muscles are attached at various points outside the bones to allow movement
What are arthropods’s exoskeleton made out of?
A substance chitin
- Attach muscles on inside of exoskeleton
What do many individual bones and segments act as?
Levers
Why do many individual bones and segments act as?
To maximize efficiency for a variety of movement
What is a “lever”?
A rod that’s a bone which is able to rotate about a fixed point known as a fulcrum, a joint
Synovial joints?
When two bones need to move against each other and are notable for the wide range of motions they allow
Where does the name ball-and-socket joint come from?
Comes from the head of a femur forming a ball that fits into a rounded socket in the pelvis bone
Pelvis and femur function?
Bones forming the ball and socket joint of the hip
Cartilage function?
A smooth protective connective tissues that lines the pelvis and femur w/in hip joint
Synovial fluid function?
Lubricating fluid w/in hip that reduces friction
Ligaments function?
Tough connective tissues that holds the bones of hip joint in place
Tendons function?
Connective tissues that connects each muscle of hip joint to its appropriate bone
Muscles function?
Muscle tissue that contracts and relaxes to allow movement of femur w/in socket of pelvis
Goniometer?
An inexpensive device used by doctors to measure the range of motion of a joint
What is range of motion?
The distance and direction that a joint can move, is usually measured in degrees
What do the movements of ribs when you breathe in and out do?
Help expand the thoracic cavity when breathing and compresses thoracic cavity when out
Position of internal intercostal muscles?
Under the external almost opposite to it.
- Lies at an angle also using ribs as their origin and insertion points
What happens when the external intercostal muscle contracts?
The expansion of the rib cage results in a stretching of the internal intercostal muscles
Locomotion?
The ability to move from a place to a place
Animals that are descended from ancestral species that once lived on land?
Marine mammals like dolphins, whales, seals
Adaptations of dolphins?
- Streamlined body - allows them to move through viscous water with ease and speed
- Lost all body hair - reduces drag in water
- Tail adapted to form fluke - allows up and down motion for propulsion
- Lost all rear legs
- Front limbs adapted to be flippers - used for steering
- Have an airway called “blowhole” on top surface of head - to exchange air at periodic intervals w/out full body leaving water
- Can seal blowhole tightly during breaths - so water doesn’t enter airway
- Can stay underwater for few mins
- Still have mammalian characteristics like being endothermic, producing milk, Advanced two sided circulatory, and long term parental care for kids
