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High school biology
Course: High school biology > Unit 8
Lesson 3: The musculoskeletal system- Skeletal structure and function
- Cartilage
- Ligaments, tendons, and joints
- Three types of muscle
- Anatomy of a skeletal muscle cell
- LeBron Asks: What muscles do we use when shooting a basket?
- The musculoskeletal system review
- The musculoskeletal system
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The musculoskeletal system review
Key terms
| Term | Meaning |
|---|---|
| Musculoskeletal system | The body system that provides support, stability, shape, and movement to the body |
| Joint | The point at which two (or more) bones meet. |
| Cartilage | Soft connective tissue found between joints |
| Ligaments | Connective tissue that attaches bone to bone at a joint |
| Tendons | Connective tissue that attaches muscle to bone |
| Voluntary muscle | Muscle that can be consciously controlled |
| Involuntary muscle | Muscle that is controlled by the autonomic nervous system (not consciously controlled) |
| Striated muscle | Muscle tissue that has a striped appearance due to its fiber composition |
The musculoskeletal system
In the musculoskeletal system, the muscular and skeletal systems work together to support and move the body.
The bones of the skeletal system serve to protect the body's organs, support the weight of the body, and give the body shape. The muscles of the muscular system attach to these bones, pulling on them to allow for movement of the body.
The human skeleton
The human skeleton performs several major functions. It protects the internal organs, supports and gives shape to the body and allows for movement.
It also is the site of blood cell production, which occurs in the marrow of some bones.
The skeleton
The human skeleton is divided into two parts: the axial skeleton and the appendicular skeleton.
The axial skeleton consists of:
- the skull, which protects the brain and supports facial structure
- the vertebral column (spine), which surrounds and protects the spinal cord and support the head
- the thoracic (rib cage), which surrounds and protects the organs within the chest (including heart and lungs)
The appendicular skeleton consists of:
- the pectoral girdle (shoulders):
- upper and lower limbs (arms and legs)
- the pelvic girdle (hip bones)
Joints, cartilage, ligaments, and tendons
The musculoskeletal system also contains connective structures and tissues that support the body and allow for its movement.
Cartilage acts as a shock absorber to reduce friction. Ligaments help stabilize the joint, keeping it from moving outside of its intended range of motion. Tendons connect the skeletal system to the muscular system by attaching muscle to bone. When muscle contracts, the tendon acts on the bone, causing movement.
Joints, the point at which two or more bones connect, can be fixed, slightly movable, or freely movable.
Muscles
The body contains three types of muscle tissue: skeletal muscle, smooth muscle, and cardiac muscle.
Skeletal muscle is voluntary and striated. These are the muscles that attach to bones and control conscious movement. Smooth muscle is involuntary and non-striated. It is found in the hollow organs of the body, such as the stomach, intestines, and around blood vessels. Cardiac muscle is involuntary and striated. It is found only in the heart and is specialized to help pump blood throughout the body.
Muscle contraction
When a muscle fiber receives a signal from the nervous system, myosin filaments are stimulated, pulling actin filaments closer together. This shortens sarcomeres within a fiber, causing it to contract.
Want to join the conversation?
If there are only voluntary and involuntary muscles, then what would your diaphragm be? You don't have to think about it contracting to breathe, but you can also stop yourself from breathing.(10 votes)
I believe that the diaphragm would be a mixture of both involuntary smooth muscles and voluntary skeletal muscles. Because you can exhale and inhale without thinking, that indicates the involuntary portion of the diaphragm. But when you take deep breaths, such as when you're meditating, you're conscious and aware of breathing and therefore voluntarily controlling your breaths, which leads to the skeletal muscle portion. Side note, I don't think there would be any cardiac involuntary muscles as that is just located in the heart. Hope that made sense.(10 votes)
what connects the skeletal system to the muscular system?(5 votes)
muscles are connected to bones thru tendon so the answer can be taken as tendon
[its been 2 yrs but hopefully if others have the same q it might be helpful](2 votes)
how does the skeletal and muscular system work together to contract and extend?(3 votes)
The bones of the skeletal system serve to protect the body's organs, support the weight of the body, and give the body shape. The muscles of the muscular system attach to these bones, pulling on them to allow for movement of the body.(4 votes)
Is all the muscles discovered in the body?(3 votes)
I'm fairly certain that they have. However it's also impossible to know. If certain muscles exist in the body that haven't been discovered, then we don't know that they exist in order to determine that they're undiscovered. Idk if that actually makes sense, sorry(4 votes)
Kinda stupid question, but are the muscles in your butt involuntary or voluntary? The article states that voluntary muscles can be contracted voluntarily and involuntary muscles move on their own autonomously. But your butt muscles don't move at all... is there a special name for them?(1 vote)- The muscles in the glutes are voluntary. Aside from the famous Gluteus Maximus, you also have the Gluteus Minimus, the Gluteus Medius, the Piriformis, the Superior Gemellus, and many more. While you might not notice them, these muscles play a role in moving and rotating the leg at the hip.
Does this help?(7 votes)
How strong are your bones?(1 vote)- it depends on which one. you femur is about three times the strength of concrete but it takes only 25 pounds to break the weakest.(7 votes)
- When watching basketball, the TV commentators will say a player is missing shots because the player's legs are getting tired. If you shoot a basket ball with your arms and hands, what do your legs have to do with it?(4 votes)
- because players run and jump(1 vote)
How exactly does the brain send messages to the muscles to contract? I tried searching for what connects them, but i can't find out what is it.(1 vote)
Single nerve cells in the spinal cord, called motor neurons, are the only way the brain connects to muscles. When a motor neuron inside the spinal cord fires, an impulse goes out from it to the muscles on a long, very thin extension of that single cell called an axon. When the impulse travels down the axon to the muscle, a chemical is released at its ending. Muscles are made of long fibers connected to each other longways by a ratchet mechanism, the kind of mechanism that allows the two parts of an extension ladder to slide past each other and then lock in a certain position. When the chemical impulse from the motor neuron hits the muscle, it causes to muscle fibers to rachet past each other, overlapping each other more, so that the muscle gets shorter and fatter. When the impulses from the nerves stop, the muscle fibers slide back to their original positions.
Each motor neuron connects to just one muscle, say the bicep on the front of your upper arm that lifts your forearm, or to the triceps, the one on the back that extends your forearm. But when you move, you never think, “I’d like to contract my bicep two inches and relax my tricep two inches” — instead you think, “I’d like to put this cake in my mouth!” How does the brain translate from the general idea to lift something to your mouth to specific commands to muscles? It does it in stages. In the cerebral cortex, the commands in the neurons there represent coordinated movements – like pick up the cake, hit the ball, salute. The cortex then connects to a sort of console in the spinal cord that overlays the motor neurons. This console lays out arm position in space, up-down, left-right. Each desired arm position then is read out as a collection of specific commands to each motor neuron and muscle.
www.ccmr.cornell.edu/faqs/how-does-your-body-move-does-the-brain-send-it-messages/(7 votes)
- how do your lungs work(3 votes)
The diaphragm, an involuntary muscle, pushes up and down to help the lungs move(2 votes)
Jeez. All the comments take place at least 3-4 years ago T-T(3 votes)
