Reduced type II muscle fiber
PhysiologicalData Availability
Period at which this change occurs is not accurately known
Tissue
-
skeletal muscle
Changes
⇩
-
Anatomical System
-
anatomical site
- head and neck
-
thorax
- thoracic wall
- abdomen
- pelvis
- perineum
- upper limb
- lower limb
- whole body
- adipose tissue
- mucosa
- spine
-
cardiovascular system
-
heart
- atrium
-
ventricle
- left ventricle
- endocardium
- myocardium
- pericardium
- cardiac valve
- cardiac conducting system
-
artery
- aorta
- arterial intima
- arterial media
- arterial adventitia
- carotid artery
- coronary artery
-
vein
- venous intima
- venous media
- venous adventitia
- capillary
-
heart
-
respiratory system
- nose
- sinus
- larynx
- trachea
- bronchus
-
lung
- alveolus
- pleura
- diaphragm
-
hematological system
-
bone marrow
- hematopoietic stem cells
- mesenchymal stem cell
-
blood
- plasma
- myeloid progenitor cell
-
bone marrow
-
lymphoreticular system
- lymph
- lymph node
- tonsil
- spleen
-
alimentary system
-
oral cavity
- tongue
- salivary gland
- tooth
- gum
-
pharynx
- nasopharynx
- oropharynx
- hypopharynx
- oesophagus
-
stomach
- gastric mucosa
-
intestine
-
small intestine
- duodenum
- jejunum
- ileum
- vermiform appendix
-
large intestine
-
colorectal
-
colon
- appendix
- rectum
-
colon
- anus
- cecum
-
colorectal
-
small intestine
- mesentery
- omentum
- peritoneum
-
liver and biliary system
- liver
- gall bladder
- bile duct
-
pancreas
- exocrine pancreas
-
oral cavity
-
urogenital system
-
urinary system
-
kidney
-
nephron
-
renal corpuscle
- glomerus
-
renal tubule
- renal proximal convoluted tubule
- renal distal convoluted tubule
- loop of Henle
- renal collecting duct
-
renal corpuscle
- renal vasculature
- glomerulus
-
nephron
- ureter
- bladder
- urethra
-
kidney
-
reproductive system
-
male reproductive system
-
testis
- seminiferous tubule
- epididymis
- prostate
- vas deferens
-
penis
- glans
- foreskin
-
testis
-
female reproductive system
- ovary
- uterine tube
-
uterus
- cervix
- endometrium
- myometrium
- vagina
- vulva
-
breast
- mammary gland
-
male reproductive system
-
urinary system
-
endocrine system
-
endocrine pancreas
- islets of Langerhans
- pineal gland
- pituitary gland
- thyroid
- parathyroid
-
adrenal gland
- adrenal cortex
- adrenal medulla
-
endocrine pancreas
-
musculoskeletal system
-
bone
- ulna
- femur
- cartilage
-
joint
- synovium
- ligament
- meniscus
-
muscle
- skeletal muscle
- smooth muscle
- tendon
- fascia
-
bone
-
integument system
-
skin
- epidermis
- dermis
-
appendages
- hair follicle
- hair
- nail bed
- nail
- sweat gland
- sebaceous gland
- subcutaneous
-
skin
-
nervous system
-
central nervous system
-
brain
-
cerebrum
-
cerebral cortex
-
frontal lobe
- prefrontal cortex
- parietal lobe
- temporal lobe
- occipital lobe
- visual
- insula
- olfactory bulb
- anterior olfactory nucleus
- lateral olfactory stria
- medial olfactory stria
- olfactory tubercle
- primary olfactory cortex
- secondary olfactory cortex
- hippocampus
- parahippocampal gyrus
-
frontal lobe
- basal nuclei
-
cerebral cortex
-
hypothalamus
- preoptic nucleus
- supraoptic nucleus
- suprachiasmatic nucleus
- paraventricular nucleus
- infundibular nucleus
- anterior nucleus
- dorsomedial nucleus
- ventromedial nucleus
- lateral nucleus
- posterior nucleus
- premamillary nucleus
- tuberomamillary nucleus
- medial mamillary nucleus
- lateral mamillary nucleus
- lateral tuberal nucleus
-
brain stem
-
midbrain
- crus cerebri
- colliculi
- substantia nigra
- red nucleus
- periaqueductal grey matter
- oculomotor nucleus
- trochlear nucleus
- mesencephalic trigeminal nucleus
-
pons
- vestibular nuclei
- cochlear nuclei
- superior olivary nucleus
- trapezoid nucleus
- nucleus of the lateral lemniscus
- abducent nucleus
- facial nucleus
- salivatory nuclei
- trigeminal nucleus
-
midbrain
-
cerebellum
- cerebellum cortex
- cerebellum nuclei
-
tract
- corpus callosum
- ventricular system
- cerebrospinal fluid
- meninges
- white matter
- grey matter
- blood brain barrier
-
cerebrum
- spinal cord
-
brain
-
peripheral nervous system
-
visual apparatus
- globe
- eyelid
- lacrimal gland
- conjunctiva
- cornea
- sclera
- lens
- vitreous humor
- iris
- ciliary body
- choroid
- retina
- optic nerve
- trabecular meshwork
-
auditory apparatus
- external ear
- middle ear
- tympanum
- auditory tube
- auditory ossicle
-
internal ear
-
osseous labyrinth
-
cochlea
- spiral organ of Corti
- semicircular canal
- vestibule
-
cochlea
- membranous labyrinth
-
osseous labyrinth
- olfactory apparatus
- peripheral nerve
- ganglion
- sympathetic chain
-
visual apparatus
-
central nervous system
-
immune system
-
thymus
- T cell progenitor
- lymphocytes
- B cell
- memory B cell
- T cell
- T regulatory cell
- stromal cell
- naïve T cell
- neutrophil
- macrophage
- natural killer cell
- dendritic cell
- leukocyte
-
thymus
-
anatomical site
-
Anatomical System
References
- Nilwik et al. (2013) "The decline in skeletal muscle mass with aging is mainly attributed to a reduction in type II muscle fiber size." Exp. Gerontol. 48(5):492-498 (PubMed)
- Lexell (1995) "Human aging, muscle mass, and fiber type composition." J. Gerontol. A Biol. Sci. Med. Sci. 50 Spec No:11-16 (PubMed)
External Links
Description
Limb muscles from older men and women are 25-35% smaller and have significantly more fat and connective tissue than limb muscles from younger individuals. Quadriceps cross-sectional area is substantially smaller in healthy older versus young men. Type II (fast-twitch) muscle fiber size is substantially smaller in the elderly versus the young, while the size of type I (slow-twitch) fibers is much less affected by age. Differences in type II muscle fiber size fully explained differences in quadriceps cross-sectional area between the two groups. Reduced muscle mass with aging is mainly attributed to smaller type II muscle fiber size.
Relationships
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Loss of muscle torque
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Muscle mass and strength loss
- Reduced type II muscle fiber
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Muscle mass and strength loss