musculoskeletal system

Question 1

list main functions of the skeleton

Answer 1

1. support
2. protection
3. movement
4. mineral storage
5. blood cell production
6. energy storage
7. endocrine regulation

Question 2

what is the longest bone in the body

Answer 2

femur (thigh)

Question 3

explain differences between the male and female skeleton

Answer 3

1. Pelvis:
   Female pelvises are generally wider and broader compared to male pelvises. accommodates childbirth.
   The pelvic inlet (the opening at the top of the pelvis) is more oval-shaped in females and heart-shaped in males.
   The angle of the pubic arch (the angle formed by the meeting of the pubic bones at the front of the pelvis) is greater in females.
2. Skull:
   Male skulls tend to be larger and more robust compared to female skulls. The shape of the mandible (lower jaw) also differs, with male mandibles often being more robust and squared.
3. Overall Size and Proportions:
   male skeletons are larger and more robust compared to female skeletons. This is evident in bone length, width, and thickness, reflecting differences in overall body size and muscle mass.
   Male long bones are longer and have larger muscle attachment sites compared to female long bones.
4. Other Skeletal Features:
   There may be subtle differences in other skeletal features, such as the shape of the thorax (chest), the curvature of the spine, and the size and shape of certain joints.

Question 4

describe the three different types of joints

Answer 4

1. Fibrous Joints:
   - presence of fibrous connective tissue between the articulating bones.
   - immovable or have limited movement and provide stability and support to the skeleton.
   - two main types:
   a. Sutures: Found only in the skull, sutures are immovable fibrous joints, sutures allow for growth and expansion of the skull during infancy and childhood while providing strength and protection to the brain.
   b. Syndesmoses: slightly movable fibrous joints where bones are connected by a ligament.
2. Cartilaginous Joints:
   - connected by cartilage and allow for limited movement.
   - These joints provide cushioning and shock absorption and are found in areas where slight movement is necessary.
   - two main types:
   a. Synchondroses: immovable cartilaginous joints where bones are joined by hyaline cartilage.
   b. Symphyses: slightly movable cartilaginous joints where bones are connected by fibrocartilage.
3. Synovial Joints:
   - most common type of joint in the body
   - presence of a synovial cavity filled with synovial fluid.
   - These joints allow for a wide range of movement and are classified into different types.
   Key features of synovial joints include:
   a. Articular Cartilage: Covers the articulating surfaces of the bones, providing smooth and low-friction movement.
   b. Joint Capsule: Surrounds the joint and consists of an outer fibrous capsule and an inner synovial membrane.
   c. Synovial Fluid: Lubricates and nourishes the joint, reducing friction and wear.
   d. Accessory Structures: Include ligaments, tendons, and bursae, which provide stability, support, and cushioning to the joint.

Question 5

understand the different subtypes of synovial joints and give examples

Answer 5

1. Hinge Joint:
   - Structure: Consists of a convex surface of one bone fitting into the concave surface of another bone.
   - Movement: Allows movement in one plane, like a door hinge, enabling flexion and extension.
   - Examples: Elbow joint, knee joint and interphalangeal joints of the fingers and toes.
2. Ball-and-Socket Joint:
   - Structure: Consists of a spherical head of one bone fitting into a cup-shaped socket of another bone.
   - Movement: Allows movement in multiple planes, including flexion, extension, abduction, adduction, and rotation.
   - Examples: Shoulder joint and hip joint
3. Pivot Joint:
   - Structure: Consists of a cylindrical surface of one bone rotating within a ring or notch of another bone.
   - Movement: Allows rotational movement around a central axis.
   - Examples: Atlantoaxial joint
4. Ellipsoidal (Condyloid) Joint:
   - Structure: Consists of an oval-shaped condyle of one bone fitting into an elliptical cavity of another bone.
   - Movement: Allows flexion, extension, abduction, adduction, and circumduction, but not rotation.
   - Examples: Radiocarpal joint and metacarpophalangeal joints
5. Saddle Joint:
   - Structure: Consists of two saddle-shaped surfaces articulating with each other, resembling a rider sitting in a saddle.
   - Movement: Allows movement in two planes, including flexion, extension, abduction, adduction, and circumduction.
   - Examples: Carpometacarpal joint of the thumb and sternoclavicular joint.
6. Gliding (Plane) Joint:
   - Structure: Consists of flat or slightly curved surfaces that glide past each other.
   - Movement: Allows sliding or gliding movements in multiple directions.
   - Examples: Intercarpal and intertarsal joints.

Question 6

describe the main functions of the muscular system

Answer 6

1. movement
2. stability and posture
3. joint stability
4. heat production
5. facilitation of circulation
6. protection of internal organs

Question 7

explain the three types of muscle in the body

Answer 7

1. Skeletal Muscle:
   - attached to bones by tendons and is responsible for voluntary movements of the body. It is characterized by its striated (striped) appearance under the microscope
   - Structure: Skeletal muscle fibers are long, cylindrical cells with multiple nuclei located at the periphery.
   - Function: Skeletal muscle contracts and relaxes in response to nervous impulses from the central nervous system. key role in walking, running, lifting, and other voluntary actions.
2. Smooth Muscle:
   - found in the walls of internal organs, blood vessels, and other structures.
   - Structure: Smooth muscle cells are smaller and shorter than skeletal muscle fibers and have a single, centrally located nucleus. They contain contractile proteins arranged in a less organized manner compared to skeletal muscle.
   - Function: Smooth muscle contracts involuntarily in response to various stimuli, such as hormones, neurotransmitters, and stretch. It regulates the diameter of blood vessels (vasoconstriction and vasodilation), controls the movement of materials through hollow organs (peristalsis), and contributes to functions such as digestion, respiration, and urination.
3. Cardiac Muscle:
   - found exclusively in the heart and is responsible for involuntary contraction of the heart chambers, pumping blood throughout the body. It has a striated appearance similar to skeletal muscle but possesses unique structural and functional properties.
   - Structure: Cardiac muscle cells, called cardiomyocytes, are branched and interconnected by intercalated discs, specialized junctions that facilitate communication and coordination between cells. Each cardiomyocyte contains a single nucleus and numerous mitochondria to support its high energy demands.
   - Function: Cardiac muscle contracts rhythmically and involuntarily to generate the force necessary to pump blood through the circulatory system. It maintains the heart’s regular beating pattern, ensuring efficient circulation of oxygenated blood to tissues and organs.

Question 8

what are the two contractile proteins

Answer 8

actin (thin)
myosin (thick)

Question 9

what is the neuromuscular junction

Answer 9

a junction between a motor neuron and a muscle