2.4 Anatomy of Circulation - HISTOLOGY

Question 1

3 LAYERS of the HEART:
(inner? middle? outer?)

Answer 1

Inner: ENDOCARDIUM

Middle: MYOCARDIUM

Outer: EPICARDIUM / VISCERAL PERICARDIUM

Question 2

the VISCERAL LAYER of SEROUS PERICARDIUM is also known as

Answer 2

EPICARDIUM

Question 3

Inner ENDOCARDIUM (inner lining) is composed of which CELL TYPE

Answer 3

SIMPLE SQUAMOUS ENDOTHELIAL CELLS

& supporting CONNECTIVE TISSUE

Question 4

MYOCARDIUM is the THICKEST LAYER, and THICKER in the…

Answer 4

LEFT VENTRICLE WALL

Question 5

MYOCARDIUM consists of..

Answer 5

CARDIAC MYOCYTES (muscle cells)

Question 6

CELL TYPE in the EPICARDIUM (VISCERAL serous pericardium)

Answer 6

SIMPLE SQUAMOUS MESOTHELIUM

supported by a thin layer of connective tissue, containing blood vessels and nerves

Question 7

what does the EPICARDIUM contain to help CUSHION the HEART

Answer 7

EPICARDIAL FAT - adipose tissue

also helps produce serous fluid for lubrication

Question 8

CHARACTERISTICS of CARDIAC MUSCLE

voluntary/involuntary?

Answer 8

INVOLUNTARY

(autonomic nervous system)

Question 9

CHARACTERISTICS of CARDIAC MUSCLE

striations or no striations?

Answer 9

STRIATED

Question 10

CHARACTERISTICS of CARDIAC MUSCLE

nucleus:

Answer 10

UNINUCLEATE

• CENTRAL

Question 11

CHARACTERISTICS of CARDIAC MUSCLE

branched or unbranched?

Answer 11

BRANCHED

Question 12

SKELETAL MUSCLE characteristics

Answer 12

• Voluntary (somatic nervous system)
• Striated
• Multinucleate (peripheral)
• Unbranched

Question 13

SMOOTH MUSCLE characteristics

Answer 13

• Involuntary
• No Striations
• Uninucleate
• Unbranched

Question 14

can CARDIAC MUSCLE REGENERATE?

Answer 14

NO produces scar tissue

(although skeletal and smooth muscle can regenerate)

Question 15

CARDIAC CELLS are CONNECTED by…

Answer 15

INTERCALATED DISCS

Question 16

3 types of CELL-CELL JUNCTIONS (INTERCALATED DISCS) between CARDIAC CELLS are

Answer 16

• FASCIA ADHERENS (‘adherence / anchoring junctions’)
• DESMOSOMES
• GAP JUNCTIONS

Question 17

what do FASCIA ADHERENS between cardiac cells help

Answer 17

Help to TRANSMIT CONTRACTILE FORCES between cells

also sites of ATTACHMENT and insertion of Thin filaments of MYOFIBRILS

Question 18

what do DESMOSOMES between cardiac cells provide

Answer 18

STRUCTURAL SUPPORT and MECHANICAL STABILTY
by binding myocytes together to prevent separation during contraction

Question 19

what do GAP JUNCTIONS between cardiac cells help

Answer 19

ELECTRICAL COMMUNICATION
(direct communication between cardiac muscle cells)

via CONNEXONS (intracellular channels / central pores that are aligned to connexons of adjacent cells)

Question 20

which INTERCALATED DISC / CELL-CELL JUNCTION type allows WAVES of DEPOLARISATION to SPREAD RAPIDLY ACROSS entire HEART (passing from cell to cell) and so coordinating action of muscle cells

Answer 20

GAP JUNCTIONS

via CONNEXONS

Question 21

which INTERCALATED DISC / CELL-CELL JUNCTION type is for STRUCTURAL SUPPORT and MECHANICAL STABILITY

Answer 21

DESMOSOMES (strong)

Question 22

which INTERCALATED DISC / CELL-CELL JUNCTION type help to TRANSMIT CONTRACTILE FORCES

Answer 22

FASCIA ADHERENS