Contraction: Muscle cells get shorter (contract) in response to nerve impulses
Muscle cells: Rod-shaped cells packed full of thinner fibres called myofibrils
Contraction
In a relaxed muscle, thick and thin myofilaments overlap each other a tiny bit. When a muscle cell is stimulated by a nerve impulse, these myofilaments slide past each other until they completely overlap. This makes th
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Human Body and Mind - Muscles Layer - Structure and contraction
Posted by humanbodyonline 344 days ago (http://www.bbc.co.uk)Human Body and Mind - Muscles Layer - Work in pairs
Posted by humanbodyonline 346 days ago (http://www.bbc.co.uk)
Muscle pairs: Muscles are grouped together in pairs on your skeleton
Relaxed or contracted: When one muscle of a pair contracts, the other relaxes
Pulling muscles
Skeletal muscles only pull in one direction. For this reason they always come in pairs. When one muscle in a pair contracts, to bend a joint for example, its counterpart then contracts and pulls in the opposite direction to strai
Relaxed or contracted: When one muscle of a pair contracts, the other relaxes
Pulling muscles
Skeletal muscles only pull in one direction. For this reason they always come in pairs. When one muscle in a pair contracts, to bend a joint for example, its counterpart then contracts and pulls in the opposite direction to strai
Human Body and Mind - Muscles Layer - Tone
Posted by humanbodyonline 346 days ago (http://www.bbc.co.uk)
Toning: Nerve impulses trigger contractions that tone your muscles
No control: You're not in control of muscle toning nerve impulses
Firm muscles
Your muscles are in a constant state of partial contraction, which keeps them firm, healthy and ready for action at all times. This is called muscle tone and it's the only aspect of skeletal muscle activity that you cannot control voluntarily. Ev
No control: You're not in control of muscle toning nerve impulses
Firm muscles
Your muscles are in a constant state of partial contraction, which keeps them firm, healthy and ready for action at all times. This is called muscle tone and it's the only aspect of skeletal muscle activity that you cannot control voluntarily. Ev
Human Body and Mind - Muscles Layer - Fast and slow twitch
Posted by humanbodyonline 349 days ago (http://www.bbc.co.uk)
Two fibres: There are two different fibres in muscle
Slow twitch muscle fibres: Contract slowly, but keep going for a long time
Fast twitch muscle fibres: Contract quickly, but rapidly get tired
Endurance or speed
Slow twitch muscle fibres are good for endurance activities like long distance running or cycling. They can work for a long time without getting tired. Fast twitch muscles are
Slow twitch muscle fibres: Contract slowly, but keep going for a long time
Fast twitch muscle fibres: Contract quickly, but rapidly get tired
Endurance or speed
Slow twitch muscle fibres are good for endurance activities like long distance running or cycling. They can work for a long time without getting tired. Fast twitch muscles are
Human Body and Mind - Muscles Layer - Facial
Posted by humanbodyonline 350 days ago (http://www.bbc.co.uk)
Attachment: Facial muscles attach to other muscles or to your skin
Expressions: Contraction of your facial muscles changes your facial expression
Expressive muscles
You contract the muscles beneath your skin as a form of non-verbal communication. Unlike your other skeletal muscles which attach to your bones, your facial muscles attach to other muscles or to your skin. This means that a tin
Expressions: Contraction of your facial muscles changes your facial expression
Expressive muscles
You contract the muscles beneath your skin as a form of non-verbal communication. Unlike your other skeletal muscles which attach to your bones, your facial muscles attach to other muscles or to your skin. This means that a tin
Human Body and Mind - Organ Layer - Voice box
Posted by humanbodyonline 352 days ago (http://www.bbc.co.uk)
System: Respiratory
Location: At the top of your windpipe
Physical description: Hollow, tubular structure about 3-4 cm across
Function: To create sounds and prevent food from entering your airways
Sound machine
Your voice box, or larynx, is a hollow tubular structure made of cartilage. It is connected to the top of your windpipe.
Inside your voice box are two bands of tissue that
Location: At the top of your windpipe
Physical description: Hollow, tubular structure about 3-4 cm across
Function: To create sounds and prevent food from entering your airways
Sound machine
Your voice box, or larynx, is a hollow tubular structure made of cartilage. It is connected to the top of your windpipe.
Inside your voice box are two bands of tissue that
Human Body and Mind - Organ Layer - Stomach
Posted by humanbodyonline 352 days ago (http://www.bbc.co.uk)
System: Digestive
Location: Between a muscular tube called the oesophagus and the small intestine
Physical description: A J-shaped elastic sac which is the widest part of your digestive system
Function: Storing food, breaking food down and mixing it with juices secreted by your stomach lining
Food store
Your stomach is a short-term food-storage facility. This allows you to consume a
Location: Between a muscular tube called the oesophagus and the small intestine
Physical description: A J-shaped elastic sac which is the widest part of your digestive system
Function: Storing food, breaking food down and mixing it with juices secreted by your stomach lining
Food store
Your stomach is a short-term food-storage facility. This allows you to consume a
BBC Science & Nature - Human Body and Mind - Organ Layer
Posted by humanbodyonline 357 days ago (http://www.bbc.co.uk)
System: Cardiovascular
Location: Between your lungs
Physical description: Grapefruit-sized and cone-shaped
Function: To pump oxygen-rich blood throughout your body and oxygen-poor blood to your lungs
Location: Between your lungs
Physical description: Grapefruit-sized and cone-shaped
Function: To pump oxygen-rich blood throughout your body and oxygen-poor blood to your lungs
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