Chapter 34.5 / 35.1 - Muscles and sensory system Flashcards
What is an example of We can only receive information about signals that we
have receptors for:
Sharks detect prey by electrical fields emitted
… so do echidnas and platypuses (mammals)
How are Sensory (signal) landscapes
changing in ways that affect
animal ecology
- Exposure to “harsh light” has the potential
to cause damage to the eyes of owls. - Sea turtles seek from patches of darkness
to lay eggs their eggs. - Marine animals such as corals and worms
use dim moonlight as a cue for reproduction.
Mechanoreception:
- respond to stretch, sound, motion, balance in the ear
- dectect physical force
- ,muscle sensors that respond to
stretch, sound, motion, balance in the ear;
Chemoreception:
-organisms respond to chemical stimuli in their environments that depends primarily on the senses of taste and smell.
- tastebuds that respond to different chemicals that hit the tongue
Electromagnetoreception:
- allows to detect earths magnetic field
- hyperpolarized while others are depolarized
- stimulated by light
What is sensory transduction?
A physical or chemical stimulus is converted
into a change in the sensory receptor’s
membrane potential.
Nerve impulse
Steps to sensory transduction?
- a protein molecule in the enviorment + combines with the protein receptor
- Na+ goes through the ion channel
- cell is depolarized
What are the functions of muscles?
- Locomotion
- Digestion
- Respiration
- Heat production
- Control of blood
flow
Muscle facts in none human animals?
- First muscle fibers common to all
animals are found in Cnidarians, which
evolved about 600 million years ago. - Muscles exert only pulling forces.
- Jellyfish have circular muscles that
contract the ”umbrella” for swimming;
when the muscles relax, the elasticity
of the umbrella causes it to expand,
stretching the circular muscles. - In most other animals, pairs of
opposing muscles are arranged to
produce movements in opposite
directions, acting on each other
through the skeletal system
What are muscles and what is its a function?
- biological motors that generate force and produce movement
- contains muscle fibers ( that generate force and change length during contraction)
- Straited/Smooth
Straited vs. Smooth
Straited: appeared striped bc its filaments are in regular repeated patterns
Smooth: myosin and actin are irregular so the muscles appeared smooth
Straited sketal
Straited cardiac
Smooth
Striated Skeletal: Connect to the Skeleton,move
limbs/torso, voluntary
Straited Cardiac: heart muscles involuntary
Smooth: Involuntary walls of arteries respirtary and digestive system
How does muscles contract?
- Fascicles contains muscle bundles: Muscle group
-Muscle bundles are composed of muscle
fibers; each fiber is a cell that uses ATP to
change length; involves action potentials. - Each muscle fiber contains hundreds of
Myofibrils—striped, rodlike organelles - Sarcomeres—repeating light and dark
bands in myofibrils
What is the sacrolemma ? What is its function?
the plasma membrane, is the site of Ca2+ action
potential conduction, which triggers muscle
contraction
What is a myobril?
Within each muscle fiber are hundreds of
myofibrils -long cylindrical organelles that
lie parallel to the muscle fiber. They are the
contractile fiber of the muscle.
How does myofibrils impact muscle growth
More myofibrils = Muscle Growth
What is the structure and function of a striated skeletal muscle?
- Myofibrils run the entire length of the muscle
fiber - Myofibrils attach to the sarcolemma at their
ends, so that as myofibrils shorten, the entire
muscle cell contracts - The striated appearance of skeletal muscle
tissue is a result of repeating bands of the
proteins actin and myosin that run along the
length of myofibrils.
Thick vs thin filaments
- Actin molecules are in thin
filaments arranged as a double
helix - myosin molecules are arranged in
parallel to form a thick filament
How does the sacromere contract?
The mechanism of muscle
contraction is the binding of
myosin to actin, which
causes the filaments to slide
by one another, causing
the sarcomere to shorten
while the filaments remain
the same length. The
contraction is 7 n
What is the Cross-Bridge Cycling?
Cross-bridge cycling forms when myosin attaches to actin, while ADP
and phosphate are still attached. This process is activated by
Calcium, which is responsible for the muscle action potential
What does the myosin do impact cross bridge cycling?
Myosin forms a strong
attachment to actin and the
myosin head changes
orientation; this tiny change of
about 10 nm is the power stroke.
The process is repeated many
times in many sarcomeres and
throughout the muscle cell,
causing contraction.
How does muscles relax?
*The motor neuron stops releasing its chemical signal, stopping
the generation of action potentials along the sarcolemma
*Ca2+ stops being released, is pumped out of the sarcolemma
*Actin binding sites on the thin filaments are ‘reshielded’
*Without the ability to form cross-bridges between thin and
thick filaments, the muscle fiber loses its tension and relaxes
