Skeletal Structure
The three main parts of the axial skeleton.
What are the skull, vertebral column, and rib cage?
The type of joint that has a fluid-filled cavity and is generally freely movable
What is synovial joint?
List four of the six overall functions of the skeletal system.
Support, protection, movement, storage, blood cell formation, hormone production
The one thing that must be available for a muscle contraction to occur.
ATP
Cords of dense connective tissue that connect muscles to bone.
What are the tendons?
Name the joint classification that is nearly all functionally synarthrotic (immovable).
What is fibrous joints?
Why are the last two pairs of ribs called “floating” ribs?
The last two pairs of ribs are only attached posteriorly to the vertebrae and are not attached anteriorly to the sternum
Explain why muscle cells contain an abundance of mitochondria.
Muscle contractions require lots of energy from ATP. Since cellular respiration occurs in the mitochondria to produce ATP , muscle cells must have many mitochondria to constantly break down sugars and generate the required energy.
The bones that make up the ankle and and the bones that make up the wrist?
What are the tarsals and carpals?
Identify the joint type that connects bones with collagen fibers.
What is fibrous joints?
A patient has paralysis of lower limbs and shows bone thinning in legs. Explain why this happens in terms of bone remodeling.
Bone remodeling is stimulated when the osteocytes receive signals such as stress/force being put on the bones (like weight-bearing) to rebuild and strengthen the bone. If these stimuli are not sent due to paralysis and lack of movement, the bone will not be regenerated and strengthened, leading to thinner, weaker bones.
Define the sliding filament model in 2–3 sentences, referencing how sarcomere components change during contraction.
Muscles contract because the basic contractile unit, the sarcomere, shortens. This occurs when the heads of myosin (thick) filaments grab the thinner actin filaments and pull them to slide past each other. This sliding action causes the filaments to overlap more (the H zone disappears ) and the Z discs to move closer together, shortening the sarcomere.
Explain two anatomical differences between the typical male and female pelvis that relate to childbirth.
Female pelvis has a wider pubic arch and a wider space around the sacrum. These features provide a wider birth canal.
For each of these joints identify whether it is synovial, cartilaginous, or fibrous:
shoulder, cranial sutures, intervertebral discs.
Shoulder: Synovial
Cranial sutures: Fibrous
Intervertebral discs: Cartilaginous
The long bone of the upper arm:
The bone that articulates with the thumb side of the wrist:
The bones that form the palm:
Humerus
Radius
Metacarpals
Name three ways muscles can increase the force of contraction.
Increase the frequency of motor neuron.
Increase the number of motor units.
Increase the size of the muscle fibers.
Place these regions of the vertebral column in correct order from neck to tail:
lumbar, cervical, sacral, thoracic, coccyx.
What is:
cervical -> thoracic -> lumbar -> sacral -> coccyx
Provide the joint names for each of the following:
(A) allows thumb opposition
(B) allows supination/pronation
(C) allows the most maneuverability.
A- saddle joint
B-Pivot joint
C-Ball and Socket joint
For each bone type (Long, Short, Flat, Irregular) give one example and explain why that bone fits its classification.
Long bone: e.g., Tibia or Femur—most of the limb bones are classified as long bones, which are typically longer than they are wide.
Short bone: e.g., Carpals (wrist bones) —they have approximately the same width, length, and height, making them roughly cube-shaped.
Flat bone: e.g., Scapula or Sternum—they have a large surface area specifically for muscle attachment.
Irregular bone: e.g., Coxal bones or Vertebrae—they have a highly specialized, complex shape and structure
Why is the nervous system critical for muscle contractions?
Skeletal muscle cells only contract voluntarily and they are excitable cells so they must be signaled by the nervous system to be simulated.