Joints and Muscles NOTES

Joints

Q: What are the three types of joints in the body?
A: Fibrous, cartilaginous, and synovial joints.

Q: What are fibrous joints?
A: Joints united by fibrous tissue, lacking a joint cavity, and allowing minimal movement.

Q: What are the types of fibrous joints?
A: Syndesmosis (e.g., splint bones & cannon bone), Suture (e.g., skull bones), and Gomphosis (e.g., teeth in sockets).

Q: What are cartilaginous joints?
A: Joints joined by cartilage, allowing limited movement.

Q: What are the types of cartilaginous joints?
A: Synchondrosis (e.g., costochondral junction) and Symphysis (e.g., pubic bones, intervertebral joints).

Q: What are the components of a synovial joint?
A: Articular surface, articular cartilage, articular cavity (joint cavity), synovial fluid, joint capsule, synovial membrane, and ligaments.

Q: What are the different types of synovial joints?
A: Hinge (elbow), Condylar (stifle), Ball & Socket (hip), Plane/Saddle (carpal/tarsal), and Trochoid (atlantoaxial joint).

Q: What is the function of ligaments?
A: Ligaments connect bone to bone and provide stability to joints.

Q: What is the function of tendons?
A: Tendons connect muscle to bone, transmitting force for movement.

Q: What is the function of menisci?
A: Menisci are fibrocartilaginous discs that cushion joints, found in the stifle and temporomandibular joints.

Q: What are bursae and their function?
A: Bursae are synovial fluid-filled sacs that reduce friction between tendons and bony prominences.

Q: What are tendon sheaths?
A: Synovial membrane-lined tubes that surround tendons and reduce friction.

Q: What are the ligaments of the stifle joint?
A: Cranial cruciate, caudal cruciate, medial cruciate, and lateral cruciate ligaments.

Muscle Types & Characteristics

Q: What are the three types of muscle in the body?
A: Skeletal, smooth, and cardiac muscle.

Q: What are the characteristics of skeletal muscle?
A: Striated, voluntary, multinucleated, and responsible for movement.

Q: What are the characteristics of smooth muscle?
A: Non-striated, involuntary, spindle-shaped, and found in hollow organs.

Q: What are the characteristics of cardiac muscle?
A: Striated, involuntary, single-nucleated, with intercalated discs for communication.

Muscle Contraction & Energy

Q: What is the role of ATP in muscle contraction?
A: ATP provides energy for myosin head movement, detachment, and calcium ion transport.

Q: What is the difference between aerobic and anaerobic pathways?
A: Aerobic respiration uses oxygen for ATP production and is more efficient, while anaerobic respiration is faster but produces lactic acid.

Q: What are actin, myosin, and the z-line?
A: Actin is the thin filament, myosin is the thick filament, and the z-line is the boundary between sarcomeres.

Q: What is the role of the sarcoplasmic reticulum in muscle cells?
A: Stores and releases calcium ions needed for muscle contraction.

Q: What role does calcium play in muscle contraction?
A: Calcium binds to troponin, allowing actin-myosin interaction and contraction to occur.

Q: What are the functional differences between Type I and Type II muscle fibers?
A: Type I (slow-twitch) fibers are fatigue-resistant with many mitochondria, while Type II (fast-twitch) fibers fatigue quickly with fewer mitochondria.

Q: What is a motor unit?
A: A motor neuron and all the muscle fibers it innervates.

Q: How do nerves stimulate muscle contraction?
A: A nerve impulse releases acetylcholine at the neuromuscular junction, triggering an action potential and muscle contraction.

Q: What are the four stages of muscle contraction?
A: Cross-bridge formation, power stroke, cross-bridge detachment, and myosin head reactivation.

Muscle Movement & Coordination

Q: What is the difference between muscle origin and insertion?
A: The origin is the fixed attachment, while the insertion moves with contraction.

Q: What are synergistic and antagonistic muscle groups?
A: Synergistic muscles work together, while antagonistic muscles work in opposition.

Q: Where can smooth and cardiac muscle be found?
A: Smooth muscle is found in hollow organs (e.g., GI tract, blood vessels), and cardiac muscle is found in the heart.

Electrocardiogram (ECG)

Q: What does an ECG measure?
A: Electrical activity of the heart.

Q: What does the P-wave represent?
A: Atrial depolarization.

Q: What does the QRS complex represent?
A: Atrial repolarization and ventricular depolarization.

Q: What does the T-wave represent?
A: Ventricular repolarization.

Q: What does the P-wave to P-wave interval represent?
A: One complete heartbeat.

Endocrinology & Hormones

Q: What is an autocrine signal?
A: A chemical signal that affects the same cell that released it.

Q: What is a paracrine signal?
A: A chemical signal that affects nearby cells.

Q: What is an endocrine hormone?
A: A hormone that travels through the bloodstream to affect distant target tissues.

Q: What are the major hormone groups?
A: Peptides/proteins (e.g., insulin), amines (e.g., epinephrine), steroids (e.g., cortisol), and eicosanoids (e.g., prostaglandins).

Q: What is a ligand?
A: A molecule that binds to a receptor to initiate a response.

Q: What is a receptor?
A: A protein that selectively binds a ligand to mediate a response.

Q: What are intracellular second messengers?
A: Molecules like cAMP, DAG, and Ca²⁺ that relay signals inside cells.

Q: Which hormones use cell-surface receptors?
A: Peptide and amine hormones.

Q: Which hormones use intracellular receptors?
A: Steroid and thyroid hormones.

Q: What is negative feedback?
A: A response that reduces further hormone release (e.g., insulin lowering blood glucose).

Q: What is positive feedback?
A: A response that amplifies hormone release (e.g., oxytocin in childbirth).

Hormone Organs & Functions

Q: What are the major hormone-producing organs?
A: Hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, ovaries, and testes.

Q: What hormones are produced by the anterior pituitary?
A: GH, prolactin, ACTH, TSH, FSH, LH.

Q: What hormones are produced by the posterior pituitary?
A: Oxytocin, ADH (vasopressin).

Q: What are the systemic effects of insulin?
A: Lowers blood glucose by promoting cellular uptake.

Q: What are the systemic effects of glucagon?
A: Raises blood glucose by stimulating glycogen breakdown.

Q: What are the systemic effects of cortisol?
A: Increases metabolism of fat, protein, and carbohydrates; stress response.

Q: What are the systemic effects of thyroid hormones (T3, T4)?
A: Regulate metabolism and energy production.

Q: What are the systemic effects of epinephrine and norepinephrine?
A: Fight-or-flight response, increased heart rate, and blood pressure.