Chapter 3 terms

Question 1

Arteries (and arterioles)

Answer 1

• Vessels that carry blood away from the heart.

- Rigid to take pressure of blood right out of heart

Question 2

Veins (and venues)

Answer 2

• Looser to expand more
• Store great quantities of blood
• Brings blood back to your heart (low pressure blood)

Question 3

capillaries

Answer 3

• Very narrow tubes between arteries and being where diffusion occurs.
• Deliver things to the cells

Question 4

Blood vessels

Answer 4

Veins
Arteries
Capillaries

Question 5

Contractile

Answer 5

It can shorten when stimulated. Its membrane is polarized, with excess Ca2+. When stimulated, ion channels on the membrane allow positive ions to rush inside. These cause actin and myosin filaments to move past each other, generating a force.

Question 6

Self-Excitable

Answer 6

Unlike skeletal muscle, cardiac muscle will spontaneously open its ion channels without a signal from a neutron. It may be singled by its neighbours, when their ions leak across the connections at the intercalated disks. (This is called depolarization, because the electrical charges were polarized before the event. The muscles must then use energy to repolarize)

Question 7

Autorhythmic

Answer 7

If not singled by an external source, cardiac muscles will depolarize with a regular rhythm, usually about every 1.5 seconds. Pacemaker cells depolarize at a faster rhythm than other cardiac muscle. (Cardiac muscles will beat regularly even if they are detached and kept in a saline medium (until they run out of energy)).

Question 8

Non-Fatiguing

Answer 8

Unlike skeletal muscles, cardiac muscles (under normal strain) can contract indefinitely without tiring or becoming damaged. It probably has to do with molecular damage done to the fibres during contractions.