Muscle's and Animal Movement

Question 1

What are the 3 types of muscle tissue in vertebrates?

Answer 1

1. skeletal
2. cardiac
3. smooth

Question 2

Functions of a skeletal muscle

Answer 2

• contract to produce movement
• sustain body posture and position
• maintain body temperature
• store nutrients and stabilise joints

Question 3

Structure of a skeletal muscle

Answer 3

• 10-100μm in diameter
• up to 75cm length
• fibres are striated by a highly organised internal arrangement

Question 4

Is a skeletal muscle voluntary or involuntary?

Answer 4

Voluntary

Question 5

Function of cardiac muscle

Answer 5

responsible for the contractility of the heart and the pumping action

Question 6

Structure of cardiac muscle

Answer 6

• striated
• not as neat as skeletal, not as messy as smooth

Question 7

Is cardiac muscle voluntary or involuntary?

Answer 7

involuntary

Question 8

Some functions of smooth muscle

Answer 8

• used in vessels to maintain blood pressure and flow
• used in the lungs to open and close airways
• used in the gastrointestinal system for motility and nutrition collection

Question 9

Is smooth muscle voluntary or involuntary?

Answer 9

Involuntary

Question 10

What does controlled contraction of muscles in vertebrates allow for?

Answer 10

movement of bones

Question 11

What is the largest group of tissues in the body of vertebrates?

Answer 11

Muscles

Question 12

Levels of organization in a skeletal muscle

Answer 12

Whole skeletal muscle(an organ) -> Muscle fibre(a single cell) -> Myofibril( a specialised intracellular structure) -> Thick and thin filaments(cytoskeletal elements) -> Myosin and actin(protein molecules)

Question 13

Skeletal muscles act in response to electrical signals to do what?

Answer 13

Convert chemical energy into mechanical energy

Question 14

Do skeletal muscles act as antagonistic pairs?

Answer 14

Typically, yes

Question 15

What are 2 factors that can be adjusted to accomplish gradation of whole-muscle tension?

Answer 15

1. the n.o muscle fibers contracting within a muscle
2. the tension developed by each contracting fiber

Question 16

The n.o fibers contracting within vertebrate muscle depends on what and why?

Answer 16

the extent of motor unit recruitment, as each whole muscle is innervated by a n.o different motor neurons

Question 17

What do vertebrate motor neurons do as they enter a muscle?

Answer 17

branch, with each axon terminal supplying a single muscle fiber

Question 18

What happens to delay or prevent fatigue during a sustained contraction involving only a portion of a muscle’s motor units?

Answer 18

Asynchronous recruitment of motor fibers takes place(ONLY FOR SUB-MAXIMAL CONDITIONS!)

Question 19

When is it impossible to alter motor unit activity to prevent fatigue?

Answer 19

during maximal contraction

Question 20

What are the determinants of whole-muscle tension in skeletal muscle - n.o fiber contracting?

Answer 20

• n.o motor units recruited
• n.o muscle fibers per motor unit
• n.o muscle fibers available to contract

Question 21

What are the determinants of whole-muscle tension in skeletal muscle - tension developed by each contracting fiber

Answer 21

• frequency of stimulation
• length of fiber at the onset of contraction
• extent of fatigue
• thickness of fiber

Question 22

3 main functions of the skeleton

Answer 22

1. structural support
2. protection
3. facilitation of movement

Question 23

3 kinds of cytoskeletal filament in eukaryotic cells

Answer 23

1. structural support
2. protection
3. facilitation of movement

Question 24

3 specialised cells in multicellular organisms that produce skeletal elements

Answer 24

1. fibroblasts
2. chondrocytes
3. osteoblasts and osteoclasts

Question 25

Function of fibroblasts

Answer 25

secrete collagen proteins that help maintain the structural framework of tissues

Question 26

Function of chondrocytes

Answer 26

responsible for the production of collagen and the extracellular matrix that will lead to the maintenance of cartilaginous tissues within joints

Question 27

Describe flagella

Answer 27

• coiled, thread-like structure
• sharp-bent
• consists of a rotary motor at its base
• composed of the protein flagellin

Question 28

What type of motion can spirochetes move in and why?

Answer 28

corkscrew motion which is allowed due to the presence of flagella

Question 29

3 examples of unicellular eukaryotes

Answer 29

1. amoeboid movement
2. swimming by means of cilia
3. swimming by means of flagella

Question 30

2 multicellular organisms that use cilia to power their locomotion

Answer 30

1. ctenophores
2. acoelomate planarians

Question 31

How do coelomates move?

Answer 31

They shorten and extend different sections of their bodies

Question 32

Example of a coelomate

Answer 32

earthworm

Question 33

2 features that allow coelomate movement

Answer 33

1. circular and longitudinal muscle layers
2. segmental compartments

Question 34

Pro and con of an exoskeleton

Answer 34

Pro - acts as ‘armor’, a protective layer
Con - demands new mechanisms of gaseous exchange and locomotion

Question 35

4 key features of vertebrates

Answer 35

1. a rigid internal skeleton supported by the vertebral column
2. an anterior skull with a large brain
3. internal organs suspended in a coelom
4. a well-developed circulatory system, driven by contractions of a ventral heart