Joints and Muscles NOTES

What are the three types of joints in the body?

Fibrous, cartilaginous, and synovial joints.

What are fibrous joints?

Joints united by fibrous tissue, lacking a joint cavity, and allowing minimal movement.

What are the types of fibrous joints?

Syndesmosis, Suture, and Gomphosis.

What are cartilaginous joints?

Joints joined by cartilage, allowing limited movement.

What are the types of cartilaginous joints?

Synchondrosis and Symphysis.

What are the components of a synovial joint?

Articular surface, articular cartilage, articular cavity, synovial fluid, joint capsule, synovial membrane, and ligaments.

What are the different types of synovial joints?

Hinge, Condylar, Ball & Socket, Plane/Saddle, and Trochoid.

What is the function of ligaments?

Ligaments connect bone to bone and provide stability to joints.

What is the function of tendons?

Tendons connect muscle to bone, transmitting force for movement.

What is the function of menisci?

Menisci are fibrocartilaginous discs that cushion joints.

What are bursae and their function?

Bursae are synovial fluid-filled sacs that reduce friction.

What are tendon sheaths?

Synovial membrane-lined tubes that surround tendons and reduce friction.

What are the ligaments of the stifle joint?

Cranial cruciate, caudal cruciate, medial cruciate, and lateral cruciate ligaments.

What are the three types of muscle in the body?

Skeletal, smooth, and cardiac muscle.

What are the characteristics of skeletal muscle?

Striated, voluntary, multinucleated, and responsible for movement.

What are the characteristics of smooth muscle?

Non-striated, involuntary, spindle-shaped, and found in hollow organs.

What are the characteristics of cardiac muscle?

Striated, involuntary, single-nucleated, with intercalated discs.

What is the role of ATP in muscle contraction?

ATP provides energy for myosin head movement, detachment, and calcium ion transport.

What is the difference between aerobic and anaerobic pathways?

Aerobic uses oxygen for ATP production; anaerobic is faster but produces lactic acid.

What are actin, myosin, and the z-line?

Actin is the thin filament; myosin is the thick filament; z-line is the boundary between sarcomeres.

What is the role of the sarcoplasmic reticulum in muscle cells?

Stores and releases calcium ions needed for muscle contraction.

What role does calcium play in muscle contraction?

Calcium binds to troponin, allowing actin-myosin interaction and contraction to occur.

What are the functional differences between Type I and Type II muscle fibers?

Type I are fatigue-resistant with many mitochondria; Type II fatigue quickly with fewer mitochondria.

What is a motor unit?

A motor neuron and all the muscle fibers it innervates.

How do nerves stimulate muscle contraction?

A nerve impulse releases acetylcholine at the neuromuscular junction.

What are the four stages of muscle contraction?

Cross-bridge formation, power stroke, cross-bridge detachment, and myosin head reactivation.

What is the difference between muscle origin and insertion?

The origin is the fixed attachment; the insertion moves with contraction.

What are synergistic and antagonistic muscle groups?

Synergistic muscles work together; antagonistic muscles work in opposition.

Where can smooth and cardiac muscle be found?

Smooth muscle is found in hollow organs; cardiac muscle is found in the heart.

What does an ECG measure?

Electrical activity of the heart.

What does the P-wave represent?

Atrial depolarization.

What does the QRS complex represent?

Atrial repolarization and ventricular depolarization.

What does the T-wave represent?

Ventricular repolarization.

What does the P-wave to P-wave interval represent?

One complete heartbeat.

What is an autocrine signal?

A chemical signal that affects the same cell that released it.

What is a paracrine signal?

A chemical signal that affects nearby cells.

What is an endocrine hormone?

A hormone that travels through the bloodstream to affect distant target tissues.

What are the major hormone groups?

Peptides/proteins, amines, steroids, and eicosanoids.

What is a ligand?

A molecule that binds to a receptor to initiate a response.

What is a receptor?

A protein that selectively binds a ligand to mediate a response.

What are intracellular second messengers?

Molecules like cAMP, DAG, and Ca²⁺ that relay signals inside cells.

Which hormones use cell-surface receptors?

Peptide and amine hormones.

Which hormones use intracellular receptors?

Steroid and thyroid hormones.

What is negative feedback?

A response that reduces further hormone release.

What is positive feedback?

A response that amplifies hormone release.

What are the major hormone-producing organs?

Hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, ovaries, and testes.

What hormones are produced by the anterior pituitary?

GH, prolactin, ACTH, TSH, FSH, LH.

What hormones are produced by the posterior pituitary?

Oxytocin, ADH (vasopressin).

What are the systemic effects of insulin?

Lowers blood glucose by promoting cellular uptake.

What are the systemic effects of glucagon?

Raises blood glucose by stimulating glycogen breakdown.

What are the systemic effects of cortisol?

Increases metabolism of fat, protein, and carbohydrates; stress response.

What are the systemic effects of thyroid hormones (T3, T4)?

Regulate metabolism and energy production.

What are the systemic effects of epinephrine and norepinephrine?

Fight-or-flight response, increased heart rate, and blood pressure.