Bone Remodeling and Vertebrae Anatomy

Bone Remodeling and Disorders

• Calcium is the divalent cation essential for creating additional bone matrix support during remodeling.
• Gravity is the primary factor in maintaining adequate bone strength through mechanical stress on weight-bearing bones.
• Osteoporosis, a bone disorder common in the elderly, leads to porous and light bones.
• Paget's disease is characterized by excessive and disorganized bone deposition and resorption.

Cervical Vertebrae

• The first cervical vertebra is called the Atlas; it lacks a body and spinous process.
• The second cervical vertebra is known as the Axis.
• The occipital bone articulates with the Atlas, enabling the nodding motion ("yes").
• The articulation between the Atlas and Axis allows for head rotation ("no").
• Occipital condyles are the skull regions that connect with the Atlas.

Anatomy of Vertebrae

• The body of a vertebra is referred to as the centrum.
• The spinous process projects in the median plane of a vertebra.
• Inferior articular processes articulate with the subsequent vertebra below.
• Vertebral foramina do not contain intervertebral discs.
• The transverse process is a lateral projection found on vertebrae.

Sternum and Ribs

• The shield-shaped top of the sternum is known as the Manubrium.
• Hyaline cartilage anchors the ribs to the sternum.
• The central portion of the sternum is referred to as the Body.
• Seven pairs of ribs articulate directly with the sternum, while five pairs are classified as false ribs, totaling 24 ribs in the rib cage.
• The head of a rib articulates in the demi-facets of thoracic vertebrae, whereas the tubercle of a rib connects with the transverse process of a vertebra.

Nervous System and Reflexes

• A significant danger of a blood clot in a cerebral artery is lack of oxygen, potentially leading to serious complications.
• CT or MRI imaging is recommended for sudden aphasia to rule out brain injury causes.
• Parkinson's disease is a progressive degenerative condition affecting dopamine pathways in the basal nuclei.
• The nervous system's basic functions do not include releasing hormones to communicate with other body cells.
• An action potential requires a threshold level depolarization to be generated, while axons contribute significantly to nerve matter.

Injury and Pathways

• Severe whiplash injuries, particularly in the C_5 and C_6 region, often involve the brachial nerve plexus.
• Morton's neuroma is a painful foot condition caused by swelling of the common plantar digital nerve, not related to nerve thinning.
• Interneurons are not required for a reflex arc, which can function with just afferent and efferent neurons.
• The lumbar section of the spinal cord includes reflex pathways that activate one muscle while inhibiting its antagonist.

Functional Areas of the Brain

• The primary visual cortex is identified at area D.
• Region A includes the prefrontal cortex, while the central sulcus is indicated by groove C.
• Region B is responsible for carrying motor commands from the cerebrum.
• The cortical regions involved in language are located in regions indicated by E.

Other Notable Conditions

• Hydrocephalus results when excess fluid cannot be distributed throughout the ventricles, leading to increased intracranial pressure.
• Ependymal cells play a role in the central nervous system structure.
• Dendrites are indicated by letter A in associated diagrams, which are key receptive regions for neurons.

Reflex Characteristics

• Sensory neurons in stretch reflexes transmit afferent impulses towards the spinal cord and increase impulse frequency upon stretch activation.
• Interneurons in the spinal cord create inhibitory synapses with motoneurons to prevent antagonist muscle contraction.
• A ventral horn injury may lead to an absent or weak patellar reflex due to damage to afferent nerve cell bodies.