NASM Section 3

Contents of the nervous system

CNS- brain and spinal cord

PNS- somatic and autonomic nervous system

Types of sensory receptors

Mechanoreceptors

Nociceptors

Chemoreceptors

Photoreceptors

2 important mechanoreceptors

1. Muscle spindle

2. Golgi tendon organ

Subdivisions of the PNS

Somatic + autonomic nervous systems

Electrolytes needed for proper function

Sodium

Potassium

Magnesium

Water

Motor skill development

1. Cognitive: use simple instructions + break down skill into smaller steps

2. Associative: help refine skills through practice + regular feedback

3. Autonomous: teach new versions of the skill to further challenge client

Human Movement System (HMS)

Collective components and structures that work together to move the body- muscular, skeletal, and nervous systems

Neuron

Specialized cell that is the functional unit of the nervous system

Three components of a neuron

1. cell body

2. axon

3. dendrites

Afferent pathway

Sensory pathway that relays information to the CNS

Efferent pathway

Motor pathway that relays information from the CNS to the rest of the body

Mechanoreceptors

Specialized structures that respond to mechanical forces (touch + pressure) within tissues and then transmit signals through sensory nerves

Somatic nervous system

Nerves that serve the outer areas of the body and skeletal muscle + are largely responsible for the voluntary control of movement

Autonomic nervous system

Division of the peripheral nervous system that supplies neural input to organs that run the involuntary processes of the body (split into sympathetic + parasympathetic)

Sympathetic nervous system

Subdivision of the autonomic nervous system that works to increase neural activity + put body into a heightened state

Parasympathetic nervous system

Subdivision of the autonomic nervous system that works to increase neural activity + put body into a more relaxed state

Proprioception

Body’s ability to naturally sense its general orientation and relative position of body parts

Muscle spindles

Sensory receptors sensitive to change in length of the muscle + the rate of the change

Golgi tendon organ (GTO)

Specialized sensory receptor located at the point where skeletal muscle fibers insert into the tendons of skeletal muscle

Sensitive to change in muscular tension + rate of tension change

Divisions of the skeletal system

• Axial

• Appendicular

Five categories of bones

1. Long

2. Short

3. Flat

4. Irregular

5. Sesamoid

5 regions of the vertebral column

1. Cervical

2. Thoracic

3. Lumbar

4. Sacrum

5. Coccyx

Intervertebral disc

Between each vertebra + acts as a shock absorber while assisting with movement

Osteokinematic

Bone/limb movement that is visible

Athrokinematic

Movement at the joint surface

Consists of rolling, sliding, and spinning

Synovial joints

• Have a synovial capsule + contain other connective tissues like ligaments and fascia to provide support

• Six classifications: gliding, condyloid, hinge, saddle, pivot, and ball-and-socket

Six classifications of synovial joints

• Gliding (plane)

• Condyloid

• Hinge

• Saddle

• Pivot

• Ball-and-socket

Skeletal system

Made of 206 bones, of which approximately 177 are used in voluntary movement

Axial skeleton

Division of the skeletal system that consists of: the skull, rib cage, and vertebral column (~80 bones)

Appendicular skeleton

Division of the skeletal system consisting of: the arms, legs, and pelvic girdle (~126 bones)

Remodeling

Process by which bone is constantly renewed by the respiration and formation of the bone structure

Osteoclasts

Special cells that break down + remove old bone tissue

Osteoblasts

Special cells that form and lay down new bone tissue

Long bones

Long, cylindrical shaft with irregular or widened ends

ex: humerus, femur

Short bones

Similar in length and width + appear somewhat cubical in shape

ex: carpals, tarsals

Flat bones

Thin, protective surfaces that provide broad surfaces for muscles to attach

ex: scapulae, sternum, ribs

Irregular bones

Unique shape and function from all other bone types

ex: vertebrae

Sesamoid bones

Small, often round bones embedded in a joint capsule or found in locations where a tendon passes over a joint

ex: patella

Depressions

flattened or indented portions of bone

Processes

Projections protruding from the bone where tendons and ligaments can attach

Cervical spine (C1-C7)

• First seven vertebrae starting at the top of the spinal column

• Form a flexible framework and provide support and motion for the head

Thoracic spine (T1-T12)

• Twelve vertebrae located in the upper and middle back behind the ribs

• Each vertebra articulates with a rib helping form the rear anchor of the rib cage

• Larger than cervical vertebrae and increase in size from top to bottom

Lumbar spine (L1-L5)

• Five vertebrae of the low-back below the thoracic spine

• Largest segments in the spinal column

• Support most of the body’s weight and are attached to many back muscles

Sacrum

• Triangular bone located below the lumbar spine

• Composed of 5 vertebrae that fuse together as the body develops into adulthood

Coccyx

• Located below the sacrum, more commonly known as the tailbone

• Composed of 3-5 small fused bones

Nonaxial

A gliding joint that moves in only one plane, either back and forth or side to side

Nonsynovial joints

Joints that have no joint capsule, fibrous connective tissue, or cartilage in the uniting structure

Myofibrils

Consist of repeating sarcomeres and actin + myosin, which create muscle contraction

Excitation-contraction coupling

Describes the steps in the muscle contraction process involving the nervous and muscular systems

Calcium and acetylcholine are involved in the process

All-or-nothing principle

Describes how a motor unit either maximally contracts or doesn’t contract at all

Type I muscle fibers

Smaller in size

Produce less force

Fatigue resistant

Used for things like sprinting

Type II muscle fibers

Larger in size

Produce more force

Fatigue quickly

Used for things like 1RM

3 types of muscle

Skeletal, cardiac, smooth

Fascia

connective tissue that surrounds muscle and bones

Epimysium

inner layer of fascia that directly surrounds an entire muscle

Fascicles

largest bundles of fibers within a muscle

surrounded by perimysium

Perimysium

connective tissue surrounding a muscle fascicle

Tendons

• connect muscle to bone

• when overstretched or torn = strain

What happens when a tendon is overstretched or torn?

A strain occurs

Ligament

• connect bone to bone

• when overstretched or torn = sprain

What happens when a ligament is overstretched or torn?

A sprain occurs

Myofibrils

• The contractile components of a muscle cell

• Myofilaments > actin and myosin are contained here

Myofilaments

filaments of a myofibril > include actin and myosin

Actin

Thin, stringlike myofilament that acts along with myosin to produce muscular contraction

Myosin

Thick myofilament that acts along with myosin to produce muscular contraction

Sarcomere

structural unit of a myofibril composed of actin and myosin filaments between 2 Z-lines

Motor unit

a motor neuron and all of the muscle fibers that it innervates

Sliding filament theory

• Series of steps in muscle contraction

• myosin and actin filaments slide past one another to produce a muscle contraction > shortening the entire length of the sarcomere

Where is the heart contained?

area called the mediastinum

Contents of the cardiorespiratory system

• heart

• blood

• blood vessels

• lungs

Where does the electrical conduction system start?

in the sinoatrial node (in the right atrium)

Sinoatrial node

• pacemaker of the heart/causes the heart to beat

• sends electrical signal to the atrioventricular node + ultimately to the ventricles

Right atrium

Gathers deoxygenated blood from the body > sends to right ventricle

Right ventricle

Pumps blood to the lungs for oxygenation

Left atrium

Receives oxygenated blood from the lungs

Left ventricle

Pumps oxygenated blood to the entire body

Pulmonary artery

Transports deoxygenated blood from the right ventricles to the lungs

Pulmonary vein

Transports oxygenated blood from the lungs to the left atrium

Stroke volume

• Amount of blood pumped out of the heart with each contraction

• end-diastolic volume - end-systolic volume

End-diastolic volume

Volume of blood in the ventricle prior to contraction

End-systolic volume

Amount of blood present in the ventricle after contraction

Cardiac output

• volume of blood pumped out of the heart in a minute

• function of heart rate and stroke volume

Capillaries

function as an exchange channel between the vessels and bodily tissues

2 phases of breathing

1. inspiration

2. expiration

What does the respiratory system do?

• Brings in oxygen

• Filters air from inspiration

• Oxygenates blood from the heart

• Exhales carbon dioxide

Normal respiratory rate

• 12-16 breaths per minute

• relies on primary respiratory muscles (diaphragm and intercostals)

Normal inspiration + exhalation

• active contraction of respiratory muscles during inhalation

• relaxation of respiratory muscles during exhalation

What happens during forced/heavy breathing?

Expiratory ventilation relies on secondary muscles to compress the thoracic cavity and force air out

Diffusion

process of getting oxygen from the environment to the body’s tissues

Bradypnea

a respiratory rate of less than 8 breaths per minute considered too slow

Tachypnea

a respiratory rate of greater than 24 breaths per minute considered too high

Transporters

Carry hormones to the intended organ or structure, where the hormones bind to a receptor to stimulate a function

What controls majority of the functions of the endocrine system?

Hypothalamus and pituitary gland

Cortisol

• stimulated by the adrenal cortex

• may be used to aid in recovery from exercise

• marker for overtraining

• sensitive to blood sugar and sleep

Glucagon

aids in the metabolism of glucose

Insulin

aids in the cellular uptake and storage of glucose

Catecholamines

• consists of epinephrine and norepinephrine

• stimulated from the adrenal medulla in response to exercise

Insulin-like growth factor

• one of the most potent anabolic hormones

• produced by the liver in response to growth hormones binding on liver receptors

How are testosterone, growth hormones, and insulin-like growth factor stimulated?

In response to anaerobic resistance training and vigorous aerobic activity

Functions of thyroid hormones

Metabolism + increasing bone mineral density through secretion of calcium