Chapter 34.5 / 35.1 - Muscles and sensory system

Question 1

What is an example of We can only receive information about signals that we
have receptors for:

Answer 1

Sharks detect prey by electrical fields emitted
… so do echidnas and platypuses (mammals)

Question 2

How are Sensory (signal) landscapes
changing in ways that affect
animal ecology

Answer 2

• 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.

Question 3

Mechanoreception:

Answer 3

• respond to stretch, sound, motion, balance in the ear
• dectect physical force
• ,muscle sensors that respond to
  stretch, sound, motion, balance in the ear;

Question 4

Chemoreception:

Answer 4

-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

Question 5

Electromagnetoreception:

Answer 5

• allows to detect earths magnetic field
• hyperpolarized while others are depolarized
• stimulated by light

Question 6

What is sensory transduction?

Answer 6

A physical or chemical stimulus is converted
into a change in the sensory receptor’s
membrane potential.

Nerve impulse

Question 7

Steps to sensory transduction?

Answer 7

1. a protein molecule in the enviorment + combines with the protein receptor
2. Na+ goes through the ion channel
3. cell is depolarized

Question 8

What are the functions of muscles?

Answer 8

• Locomotion
• Digestion
• Respiration
• Heat production
• Control of blood
  flow

Question 9

Muscle facts in none human animals?

Answer 9

• 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

Question 10

What are muscles and what is its a function?

Answer 10

• biological motors that generate force and produce movement
• contains muscle fibers ( that generate force and change length during contraction)
• Straited/Smooth

Question 11

Straited vs. Smooth

Answer 11

Straited: appeared striped bc its filaments are in regular repeated patterns

Smooth: myosin and actin are irregular so the muscles appeared smooth

Question 12

Straited sketal

Straited cardiac

Smooth

Answer 12

Striated Skeletal: Connect to the Skeleton,move
limbs/torso, voluntary

Straited Cardiac: heart muscles involuntary

Smooth: Involuntary walls of arteries respirtary and digestive system

Question 13

How does muscles contract?

Answer 13

• 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

Question 14

What is the sacrolemma ? What is its function?

Answer 14

the plasma membrane, is the site of Ca2+ action
potential conduction, which triggers muscle
contraction

Question 15

What is a myobril?

Answer 15

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.

Question 16

How does myofibrils impact muscle growth

Answer 16

More myofibrils = Muscle Growth

Question 17

What is the structure and function of a striated skeletal muscle?

Answer 17

• 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.

Question 18

Thick vs thin filaments

Answer 18

• Actin molecules are in thin
  filaments arranged as a double
  helix
• myosin molecules are arranged in
  parallel to form a thick filament

Question 19

How does the sacromere contract?

Answer 19

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

Question 20

What is the Cross-Bridge Cycling?

Answer 20

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

Question 21

What does the myosin do impact cross bridge cycling?

Answer 21

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.

Question 22

How does muscles relax?

Answer 22

*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