5.1.5 Animal responses (Muscles)

Question 1

what is a muscle

Answer 1

muscles are effectors, stimulated by motor neurones from the CNS

Question 2

What are some general features of muscles?

Answer 2

• Antagonistic e.g. Biceps and Triceps
• Made of muscle fibres, able to relax and contact
• good blood supply to supply oxygen and nutrients while removing waste products

Question 3

What are the 3 types of muscle?

Answer 3

1) SKELETAL (striated) muscle
2) SMOOTH (Unstriated) muscle
3) CARDIAC muscle

Question 4

what is skeletal muscle like?

Answer 4

Attached to bone, concerned with locomotion; quickly contracts but also quickly fatigues.
It is controlled by the voluntary/somatic nervous system – CEREBRUM and CEREBELLUM

Question 5

what is smooth muscle like?

Answer 5

Found in the walls of tubular organs and is concerned with movement of materials through them. It contracts slowly but fatigues slowly.
It is spontaneously active i.e. involuntary and controlled by the autonomic nervous system from the MEDULLA OBLONGATA

Question 6

What is Cardiac muscle like?

Answer 6

found only in the heart; contracts spontaneously and does not fatigue. Controlled by the autonomic nervous system from the MEDULLA OBLONGATA
-Cardiac muscle comes in 3 types: ATRIAL and VENTRICULAR MUSCLE and EXCITATORY and CONDUCTIVE MUSCLE FIBRES

Question 7

What are the similarities between all muscle types?

Answer 7

• Muscles tissues are composed of elongated cells called fibres which can relax and contract
• The contraction is due to protein filaments in the fibres called ACTIN and MYOSIN
• The plasma membrane of the fibre cells is called the SARCOLEMA
• The cytoplasm of the fibre cells is called the SARCOPLASM
• The sarcoplasm contains many MITOCHONDRIA to produce ATP for muscle contraction
• The rough endoplasmic reticulum is called the SARCOPLASMIC RETICULUM

Question 8

What are the features of Atrial and Ventricular muscle in Cardiac muscle

Answer 8

-Contraction of ATRIAL AND VENTRICULAR MUSCLE is powerful like skeletal muscle but is of a LONGER DURATION and does not fatigue

Question 9

What are the features of Excitatory and conductive tissue in cardiac muscle?

Answer 9

-EXCITATORY AND CONDUCTIVE FIBRES contract WEAKLY; their main function is to
CONDUCT ELECTRICAL IMPULSES (like the SAN) and CONTROL THE CARDIAC
CYCLE.
-This tissue is MYOGENIC and so can contract by itself without impulses from the CNS