1 “List and describe the functions of bones”
Bones form the skeleton, which provides the structure of the body, and are made of connective tissue
2 “Describe the classes of bones”
There are 206 bones in the adult human body, each of those bones falls into one of five classes based on their shape
Long bones are longer than they are wide and function as levers because they move when muscles contract
Short bones are generally cube-shaped and provide support for other structures
Flat bones are typically thin and often curved, they often function as connection points for other structures
Irregular bones do not fall into any other classifications and serve a variety of functions throughout the body. The vertebrae and facial bones have unique shapes that are dissimilar to any other bones in the body and fall into the irregular classification
Sesamoid bones are shaped like sesame seeds and protect tendons from compressive force
3 “Discuss the process of bone formation and development”
During early embryonic development, fibrous membranes and hyaline cartilage make up the bones of the skeleton
4 “Explain how bone repairs itself after a fracture”
When a bone is fractured, it must be placed in the correct anatomical position or the healing process will fuse the bone fragments together incorrectly
5 “Discuss the effect of exercise, nutrition, and hormones on bone tissue”
Like other organ systems in the human body, the skeletal system is dependent on other bodily processes. Exercise, or mechanical stress, is required to keep bones hard. Without mechanical stress, bones weaken and can even lose mass. Certain nutrients, such as Calcium and Vitamin D, are critical to the health of bones
6 “Describe how an imbalance of calcium can affect bone tissue”
An imbalance of calcium is known as either hypocalcemia, low levels of calcium, or hypercalcemia, high levels of calcium, and can impact nearly every aspect of life
1 “Describe the functions of the skeletal system and define its two major subdivisions”
The skeletal system consists of bones, cartilage, and ligaments, and forms the internal framework of the body
The axial skeleton provides the upright frame of the body and includes the head, neck, chest, and back
2 “Identify the bones and bony structures of the skull, the cranial suture lines, the cranial fossae, and the openings in the skull”
The skull is comprised of the braincase, which is comprised of several fused bones, the upper and lower jaws, nose, orbits, and other structures
3 “Discuss the vertebral column and regional variations in its bony components and curvatures”
The vertebral column protects the spinal cord from the upper neck to the pelvis and is often referred to as the spine or spinal column. The vertebral column is comprised of individual vertebra, each of which is separated by an intervertebral disc
The vertebral column consists of 33 vertebrae, which is eventually reduced to 24 as the bones fuse as they mature
4 “Describe the components of the thoracic cage”
The thoracic cage is often known as the rib cage and provides safety to internal organs and other soft tissues
5 “Discuss the embryonic development of the axial skeleton”
Embryonic development refers to the development that occurs while an embryo is in utero. The axial skeleton refers to the bones of the head, neck, back, and chest. The axial skeleton begins to develop early in embryonic development
1 “Discuss the bones of the pectoral and pelvic girdles, and describe how these unite the limbs with the axial skeleton”
The pectoral girdle refers to the bones that attach the upper limbs to the axial skeleton, also known as the shoulder girdle, and is comprised of the scapula and clavicle
2 “Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand”
The arm, forearm, wrist, and hand all comprise the upper limb
The arm is comprised of only the humerus, which is the long bone of the upper arm. The head of the humerus enters the glenoid cavity of the scapula, which allows the arm to move
The forearm is comprised of the radius and ulna, which run parallel from the humerus to the wrist. The radius is on the lateral, thumb, side and the ulna is the medial bone
There are eight carpal bones that comprise the wrist
The hand contains five elongated metacarpal bones, the bones are between the wrist and the fingers
3 “Identify the features of the pelvis and explain how these differ between the adult male and female pelvis”
The pelvis is comprised of four bones, the left and right hip bones, the sacrum, and the coccyx
4 “Describe the bones of the lower limb, including the bones of the thigh, leg, ankle, and foot”
The lower limbs are divided into three regions, the thigh, the leg, and the foot
5 “Describe the embryonic formation and growth of the limb bones”
Limb bones begin to form during embryonic formation. The bones begin as an embryonic tissue known as mesenchyme and can differentiate into bone and muscle tissue
1 “Discuss both functional and structural classifications for body joints”
Joints are connections where adjacent bones are joined and articulate or move around. The structural classifications of joints refer to whether the bones are connected by fibrous connective tissue or if there is a fluid-filled joint cavity connecting them
Structural classifications are divided into fibrous joints, cartilaginous joints, and synovial joints. Fibrous joints are held together by fibrous connective tissue. Cartilaginous joints are held together by a type of cartilage. In synovial joints, bones are not actually in contact but are connected through a fluid-filled joint cavity that provides lubrication. Most joints in the body are synovial joints
Functional classifications are used to define whether a joint is immobile, slightly moveable, or freely moveable. Some joints are held together so tightly by fibrous connective tissue; they are functionally immobile. On the other end of the spectrum, all synovial joints are classified as freely moveable.
2 “Describe the characteristic features for fibrous, cartilaginous, and synovial joints and give examples of each”
Fibrous joints are held together tightly by fibrous connective tissue. Examples often include joints between bones that protect organs. The pelvis, cranial sutures on the skull, and the sternum are all classified as fibrous joints because the joints effectively fuse the bones together.
Cartilaginous joints are held together by one of two types of cartilage
Diarthrosis joints are freely moveable and are mostly made up of synovial joints. The appendicular skeleton is where most diarthrosis joints are found, providing highly mobile movements. Examples include the hip and shoulder joints, which are further classified as multiaxial.
3 “Define and identify the different body movements”
Movements are contractions or relaxation of muscles resulting in movement of bones at each joint. There are several types of movement, and they are often characterized by how they vary from the anatomical position.
Flexion and extension refer to movements within the sagittal plane. Forward and backward movement of limbs, such as kicking back and forth or shaking the head “yes” would be movements within the sagittal plane.
Adduction and abduction movements occur along the coronal plane. Movement along the coronal plane would include raising the arm to the side and back.
Circumduction is a circular movement of a region of the body, traversing the sagittal and coronal plane. While stationary, moving the feet or hands in a circular motion would be an example of circumduction.
Rotation is a twisting movement within the vertebral column, at a pivot joint, or a ball-and-socket joint, such as the shoulder or hip
Supination and pronation are movements of the forearm
Dorsal and plantar flexion are the movements of the ankle. The movement is achieved when the foot points up and down.
Inversion and eversion are the movements of the feet. When the foot turns inward toward the midline or outward, the movement is achieved.
Protraction and retraction occurs in the jaw and shoulder. The movement is achieved when the joint is moved forward or back from the natural position. Depression and elevation also occur in the jaw and shoulder; they refer to up and down movements. Excursion is the side-to-side movement of the lower jaw. Superior and interior rotation occurs in the glenoid cavity of the shoulder, they refer to up and down rotations along the coronal plane.
Opposition refers to the movement of the thumb. The movement occurs when the tip of the thumb touches another finger.
4 “Discuss the structure of specific body joints and the movements allowed by each”
The knee, elbow, and ankle are all synovial and hinge joints. Hinge joints allow flexion and extension movements on the sagittal plane from the anatomical position. Kicking or raising the hand to the shoulder are examples of the movement.
The hip and shoulder are ball-and-socket joints. Ball-and-socket joints allow movement along all axes. The joint allows movement in any direction along the coronal or sagittal plane from the anatomical position.
5 “Explain the development of body joints”
Joints begin to form in conjunction with associated bones while in embryonic development. The same tissue that begins the creation of bones and associated tissues, mesenchyme, begins the creation of the joints for the body. Until the developing bones grow enough to be close, the gaps are known as fontanelles. Over time, connective tissue will begin to bind the bones together.
1 “Explain the organization of muscle tissue”
Muscle tissue is organized into three types: skeletal muscle, cardiac muscle, and smooth muscle
2 “Describe the function and structure of skeletal, cardiac muscle, and smooth muscle”
Skeletal muscle contracts and relaxes to cause movement. Skeletal muscles contract and adjust constantly to maintain a balanced and upright posture
Cardiac muscle is only found in the heart and has unique properties compared to the other types of tissues. The muscle contracts in a highly coordinated rhythm to allow blood to pump through from one ventricle to the next until the leaves the heart. The heart is responsive to the autonomic nerve system (ANS), as well as some hormonal signals, to regulate blood pressure
Smooth muscle makes up the walls of hollow organs such as the stomach, intestines, uterus, and bladder
3 “Explain how muscles work with tendons to move the body”
Skeletal muscles work with tendons to move the bones of the body. The muscles attach to the bones directly through the tendons allowing contractions to pull on bones to achieve movement.
4 “Describe how muscles contract and relax”
A muscle contraction occurs when a muscle fiber becomes thicker and shorter, often putting pressure on the tendons and bones resulting in actuation. Muscles contract when electrical signals are applied to the tissue through motor neurons. When the signal stops, the muscle relaxes. When the stimulation of the muscle ceases and the muscle relaxes, the tendons and bones return to their resting position.
5 “Define the process of muscle metabolism”
Muscles require energy to contract, but not all muscles require the same amount of energy to perform their function. Muscles require energy in the form of ATP, oxygen, and other nutrients to perform. When that energy is consumed, it produces what is known as metabolic waste.
6 “Explain how the nervous system controls muscle tension”
The nervous system controls muscle tension by carefully applying electrical impulses as needed to perform a function. Each muscle fiber is innervated by only one motor neuron, the group of fibers are controlled by another motor neuron known as a motor unit
7 “Relate the connections between exercise and muscle performance”
Muscle performance can be improved or lessened by the frequency and intensity of exercise. With age or simply lack of exercise, muscles can atrophy. Certain disorders, such as Muscular Dystrophy, can result in muscle atrophy early in life and prevent hypertrophy, or muscle growth. The metabolism of muscles can also be improved through exercise. Muscle metabolism is the amount of exertion and energy needed to perform a function – when muscles are trained to do a specific task, the energy cost goes down and efficiency improves.
8 “Explain the development and regeneration of muscle tissue”
Muscle begins to develop early during the embryonic development. The number of muscle cells are fixed during development, but satellite cells can facilitate protein synthesis required for muscle growth and development. The satellite cells are able to regenerate, but their primary purpose is to repair living tissue. Smooth muscle, unlike skeletal and cardiac muscles, can regenerate by use of pericyte, a type of stem cell found in small blood vessels. With very few exceptions, cardiac muscle is unable to repair, and will instead be replaced with scar tissue in the event that tissue death occurs.
1 “Describe the actions and roles of agonists and antagonists”
The principle muscle in a movement, such as the bicep in actuating the forearm, is known as the agonist
2 “Explain the structure and organization of muscle fascicles and their role in generating force”
A bundled group of muscle fibers are known as fascicles. Those bundled groups are covered by a layer connective tissue called perimysium
3 “Explain the criteria used to name skeletal muscles”
The names of skeletal muscles often use Latin or Greek words with one or more roots to explain what and where it is on the body. In short, the word tells the reader where the muscle is and the roots are modifiers that explain exactly which part of the muscle group. An example of this would be the pectoral muscles. The word “pectoral” refers to the breast, “major” or “minor” further refines the term to tell the reader whether it is the larger or smaller muscle group.
4 “Identify the skeletal muscles and their actions on the skeleton and soft tissues of the body”
Skeletal muscles actuate the parts of the body to allow movement. Skeletal muscles connect to bones through tendons and other tissues to allow movement. The skeletal muscles, along with bones, also function to protect some internal organs. The chest and stomach, in particular, are protected by skeletal muscles by serving as both a barrier and as tissue holding the bones of the chest and spine together.
5 “Identify the origins and insertions of skeletal muscles and the prime movements”
The moveable end of a muscle attached to a bone is called the insertion. For example, where the bicep attaches to the forearm would be referred to as the insertion. The fixed end of a muscle is called the origin. And example of an origin would be where the bicep attaches to the shoulder. When the bicep contracts, the insertion point actuates the forearm while leaving the origin with almost no movement. When the bicep relaxes, the origin remains nearly fixed while the insertion extends allow the forearm to extend.
OpenSTAX. (2018, April 9). Anatomy & Physiology. OpenSTAX CNX. Retrieved from http://firstname.lastname@example.org