Cells To Life
Week 6 Notes
Tissue Histology III
(Epithelial (glandular/membrane), Connective, Muscle, Nervous)
MUSCLE AND NERVOUS TISSUE
Muscle Tissue:
• 3 Types
o Skeletal
§ Attaches to bone for movement (voluntary)
§ Long, Cylindrical
§ Multinucleated
§ Obvious striations àsarcomeres.
o Smooth
§ In the walls of visceral organs – eg. GI
tract/urinary tract/birth canal
§ Spindle-shaped cells
§ Central nuclei
§ No striations à no sarcomeres
§ Cells arranged closely to form sheets (often
opposing-laterally perpendicular)
§ Usually involuntary – Controlled by the
autonomic nervous system
o Cardiac
§ Makes up the heart.
§ Long, Branched, Cylindrical
§ Striations à sarcomeres
§ Usually single-nucleated
§ Intercalated discs – cell membranes of 2
adjacent cells bound mechanically
(desmosomes), chemically & electrically (gap
junctions). Essentially makes the entire heart
one single muscle.
§ Involuntary – controlled by autonomic nervous
system
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, • Functions:
o Movement (specialised for contraction)
o Maintains posture
o Stabilises joints
o Generates heat
Contractile Stuff:
• Contractile Proteins Actin & Myosin à Myofilaments:
- Molecular Level
- Form assemblies within muscle cells that slide over each other resulting in contraction
o known as myofilaments (muscle-filaments) and are of 2 Types:
§ Actin
• Thin Filaments
• Helical Structure
§ Myosin
• Thick Filaments
• More complex structure àthicker
Myofilaments (Actin & Myosin)
www.MedStudentNotes.com
Week 6 Notes
Tissue Histology III
(Epithelial (glandular/membrane), Connective, Muscle, Nervous)
MUSCLE AND NERVOUS TISSUE
Muscle Tissue:
• 3 Types
o Skeletal
§ Attaches to bone for movement (voluntary)
§ Long, Cylindrical
§ Multinucleated
§ Obvious striations àsarcomeres.
o Smooth
§ In the walls of visceral organs – eg. GI
tract/urinary tract/birth canal
§ Spindle-shaped cells
§ Central nuclei
§ No striations à no sarcomeres
§ Cells arranged closely to form sheets (often
opposing-laterally perpendicular)
§ Usually involuntary – Controlled by the
autonomic nervous system
o Cardiac
§ Makes up the heart.
§ Long, Branched, Cylindrical
§ Striations à sarcomeres
§ Usually single-nucleated
§ Intercalated discs – cell membranes of 2
adjacent cells bound mechanically
(desmosomes), chemically & electrically (gap
junctions). Essentially makes the entire heart
one single muscle.
§ Involuntary – controlled by autonomic nervous
system
www.MedStudentNotes.com
, • Functions:
o Movement (specialised for contraction)
o Maintains posture
o Stabilises joints
o Generates heat
Contractile Stuff:
• Contractile Proteins Actin & Myosin à Myofilaments:
- Molecular Level
- Form assemblies within muscle cells that slide over each other resulting in contraction
o known as myofilaments (muscle-filaments) and are of 2 Types:
§ Actin
• Thin Filaments
• Helical Structure
§ Myosin
• Thick Filaments
• More complex structure àthicker
Myofilaments (Actin & Myosin)
www.MedStudentNotes.com
