Pt 2 flashcards

Epiphysis: Ends of long bones. o Shaft (diaphysis): Long, cylindrical part of the bone. o Periosteum: Connective tissue covering the outer surface of bone. o Endosteum: Connective tissue lining the inner surface of bone. o Central canal (Haversian canal): Contains blood vessels and nerves within compact bone.

💀Bones and Joints

• o Immovable joints (Synarthrosis): Example: sutures in the skull. o Freely movable joints (Diarthrosis): Example: shoulder, knee. o Joints with limited movement (Amphiarthrosis): Example: vertebrae. Types of Joints:

🦴Ossification and the Skeletal System

• o Intramembranous ossification: Bone formation directly from mesenchymal tissue (e.g., skull bones). o Endochondral ossification: Bone formation from cartilage (e.g., long bones). Ossification Types: • o 206 bones in the adult human skeleton. o Axial skeleton: Skull, vertebral column, rib cage. o Appendicular skeleton: Limbs and girdles. Skeletal System:

💀Sinuses, Spinal Column, and Ribs

• Sinuses: Air-filled spaces in the skull bones (frontal, paranasal, maxillary). The maxillary sinus is the largest. • o Cervical: 7 vertebrae (C1-C7) o Thoracic: 12 vertebrae (T1-T12) o Lumbar: 5 vertebrae (L1-L5) o Sacrum: 5 fused vertebrae in adults (1 in babies) o Coccyx: 4 fused vertebrae in adults (1 in babies) o Adults have 26 vertebrae (33 in babies before fusion). Spinal Column (Vertebral Column): • Ribs:

o True ribs (1-7): Directly attached to the sternum. o False ribs (8-12): Indirectly attached to the sternum or not attached at all. o Floating ribs (11-12): A type of false rib, not attached to the sternum.

🤔Miscellaneous Bone Questions

• The pelvis is considered an irregular bone. • The flat bones of the skull are generally less dense/heavy than the ball of the foot.

Muscles, Nerves, and Cells

• Acetylcholine (ACH): A neurotransmitter that plays a crucial role in muscle contraction and nerve impulse transmission. • o Tendons: Connect muscle to bone. o Ligaments: Connect bone to bone. Muscle Attachments: • Troponin and Tropomyosin: Proteins involved in muscle contraction regulation. Tropomyosin blocks the myosin-binding sites on actin, preventing muscle contraction. Troponin, when bound to calcium, moves tropomyosin to allow contraction. • o Rough ER: Studded with ribosomes; involved in protein synthesis. o Smooth ER: Lacks ribosomes; involved in lipid synthesis. Endoplasmic Reticulum (ER): • o ATP (Adenosine Triphosphate): The primary energy currency of cells. o ADP (Adenosine Diphosphate): Formed when ATP loses a phosphate group, releasing energy. ATP and ADP: • Agonist and Antagonist Muscles: Agonist muscles produce a movement, while antagonist muscles oppose that movement. • o Excitable: Respond to stimuli. o Contractible: Can shorten. o Extensible: Can be stretched. o Elastic: Return to their original shape after stretching. Muscle Specifications: • Cell at Rest: High potassium concentration inside the cell and high sodium concentration outside. Sodium channels open when the cell is stimulated, causing depolarization.

• Neuron Structure: Consists of the cell body (soma), dendrites (receive signals), axon (transmits signals), myelin sheath, and Nodes of Ranvier • Myelin Sheath: Insulating layer around axons formed by oligodendrocytes (CNS) and Schwann cells (PNS), allowing for faster nerve impulse conduction. Gaps in the myelin sheath are called Nodes of Ranvier. • Central Nervous System (CNS): Brain and spinal cord. Everything else is part of the Peripheral Nervous System (PNS).

This detailed guide is intended as a helpful learning resource. Remember to consult additional resources and your textbook for a comprehensive understanding of the material.

Detailed Notes on Skeletal System, Muscle Proteins, and Nervous System Function

Skeletal System

The skeletal system, comprised of 206 bones, is divided into two main divisions:

• Axial Skeleton: Forms the central axis of the body and includes the skull, vertebral column (spine), and rib cage. Its primary function is to protect vital organs like the brain, heart, and lungs. • Appendicular Skeleton: Consists of the bones of the appendages (arms and legs), along with the pectoral (shoulder) and pelvic girdles that attach the limbs to the axial skeleton. This division is primarily involved in movement.

Bone Shapes

Bones are categorized into four main shapes based on their structure and function:

• Long Bones: Longer than they are wide, functioning as levers for movement. Examples include the femur (thigh bone) and humerus (upper arm bone).

• Short Bones: Roughly cube-shaped, providing stability and some limited movement. Carpals (wrist bones) and tarsals (ankle bones) are examples of short bones. • Flat Bones: Thin and flattened, offering protection to underlying organs and large surface areas for muscle attachment. Examples include the skull bones, ribs, and sternum (breastbone). The pelvis is also considered a flat bone. • Irregular Bones: Bones with complex shapes that do not fit into the other categories, often having specialized functions related to their unique shapes. Vertebrae and facial bones are examples of irregular bones.

Actin and Myosin

Actin and myosin are two crucial proteins involved in muscle contraction.

• Actin: Forms thin filaments within muscle fibers. Tropomyosin is another protein that blocks the binding site on actin, preventing interaction with myosin when the muscle is at rest. • Myosin: Forms thick filaments and has heads that bind to actin, creating cross- bridges.

The interaction between actin and myosin, regulated by troponin and tropomyosin, generates the force necessary for muscle contraction.

Nervous System Function

The nervous system is the body's primary communication and control network. It has two main divisions:

• Central Nervous System (CNS): Comprises the brain and spinal cord. It processes information received from the body and sends out instructions. Oligodendrocytes produce the myelin sheath that insulates axons in the CNS, speeding up nerve impulse transmission. • Peripheral Nervous System (PNS): Includes all nerves outside the brain and spinal cord. The PNS transmits sensory information to the CNS and carries motor commands from the CNS to muscles and glands. Schwann cells produce the myelin sheath in the PNS.

Key functions of the nervous system include:

• Sensory Input: Detecting internal and external stimuli through specialized receptors. • Integration: Processing and interpreting the sensory information within the CNS. • Motor Output: Responding to stimuli by activating muscles (for movement) or glands (for secretion).

Neurotransmitters: Chemical messengers that transmit signals across synapses (gaps between neurons). Acetylcholine (ACh) is a key neurotransmitter involved in various nervous system functions, including muscle contraction