Three Systems within Human Body
Nervous, skeletal, and muscular
Kinetic Chain
Three systems responsible for human movement
Human Movement System
The combination and interrelation of the nervous, muscular, and skeletal systems
Nervous System
A conglomeration of billions of cells specifically designed to provide a communication network within the human body
Two Parts of Nervous System
- Central (brain and spinal cord)
2. Peripheral (nerves)
Three Primary Functions of Nervous System
- Sensory: sense changes in environment
- Integrative: analyze and interpret information
- Motor: neuromuscular response to sensory information
Proprioception
Body’s ability to sense the relative position of adjacent parts of the body
Training this ability will improve balance, coordination, and posture
Decreases risk of injury
Neuron
Functional unit of the nervous system
Sensory (afferent) neurons
Transmit nerve impulses from effector sites (such as muscles and organs) via receptors to the brain and spinal cord
Three main parts of the neuron
- Cell body: contains nucleus and other organelles
- Axon: transmits nervous impulses to other neurons or effector sites; provides communication from the brain and spinal cord to other parts of body
- Dendrites: gather information from other structures and transmit it back into the neuron
Three functional classifications of neurons
- Sensory (afferent) neurons: respond to touch, sound, light, and other stimuli; transmit nerve impulses from effector sites to brain and spinal cord
- Interneurons: transmit nerve impulses from one neuron to another
- Motor neurons: transmit nerve impulses from the brain and spinal cord to the effector sites
(touching a hot object)
Central Nervous System
Brain and spinal cord; coordinate the activity of all parts of the body
Peripheral Nervous System
Nerves that connect the CNS to the rest of the body and the external environment.
Consists of 12 cranial nerves, 31 pairs of spinal nerves, and sensory receptors.
Two Functions of Peripheral Nerves
- Provide a connection for the nervous system to activate different effector sites, such as muscles
- Relay information from the effector sites back to the brain via sensory receptors
Subdivisions of PNS
- Somatic Nervous System: nerves that serve outer areas of the body; responsible for voluntary movement
- Autonomic Nervous System: supplies neural input to the involuntary systems of the body
Subdivisions of Autonomic System
- Sympathetic: increase levels of activation in preparation for activity
- Parasympathetic: decrease levels of activation during periods of rest and recovery
4 Types of Sensory Receptors
- Mechanoreceptors: respond to mechanical forces
- Nociceptors: respond to pain
- Chemoreceptors: respond to chemical interaction
- Photoreceptors: respond to light
Muscle Spindles
Sensory receptors within muscles that run parallel to the muscle fibers and are sensitive to change in muscle length and rate of length change
Rapid neural response is designed as a protective mechanism to prevent overstretching and potential muscle damage
Golgi tendon organs
Specialized sensory receptors located at the point where skeletal muscle fibers insert into tendons of skeletal muscle
Activation of the golgi tendon organs will cause the muscle to relax which prevents the muscle from excessive stress or possibility of injury
Joint receptors
Located in and around the joint capsule, and they respond to pressure, acceleration, and deceleration of the joint
Signal extreme joint positions and help to prevent injury
Skeletal System
Provides shape and form for our bodies in addition to supporting, protecting, allowing bodily movement, producing blood for the body, and storing minerals
Growth, maturation, and functionality of the skeletal system are greatly affected by __________
posture, physical activity, and nutrition
Two Parts of Skeletal System
- Axial: skull, rib cage, and vertebral column
2. Appendicular: upper and lower extremities, shoulder, pelvic girdles
Remodeling
Process of resorption and formation of bone
