Human Anatomy: Skeletal and Muscle Systems

Ligaments

• Ligaments connect bone to bone.

Skeletal System Functions

• Support
• Mineral and lipid storage
• Blood cell production
• Protection
• Leverage

Energy Reserve

• Glycogen is an important energy reserve found in the liver and skeletal muscle.

Bone Production

• Osteoblasts are responsible for producing new bone.

Muscle Tissue Types

• Skeletal muscle: Voluntary movement (e.g., biceps brachii)
• Cardiac muscle: Involuntary; pumps blood (e.g., myocardium)
• Smooth muscle: Involuntary; moves substances through internal organs (e.g., stomach walls)

Goosebumps

• Goosebumps are caused by the contraction of arrector pili muscles in hair follicles. This is triggered by cold temperatures or emotional responses. Contraction causes hairs to stand up, trapping air and creating insulation.

Muscle Relaxation

• ATP is essential for muscle relaxation, releasing cross-bridges.

Cellular Respiration

• Cellular respiration converts glucose and oxygen into energy (ATP), with carbon dioxide and water as byproducts. This occurs in the mitochondria.

Calcium Ions in Muscle Contraction

• Calcium ions are released from the sarcoplasmic reticulum.

Muscle Outer Layer

• The outermost layer of collagen fibers surrounding the entire muscle is the epimysium.

Muscle Striations

• All muscles, except smooth muscle, exhibit striations.

Bone Growth Plate

• The growth plate is called the epiphyseal plate.

Melanin Production

• Melanocytes manufacture and store melanin.

Bone Outer Surface

• The outer surface of a bone is the periosteum.

Skin Functions

• Protection
• Excretion/secretion
• Sensory reception

Metabolism's Main Product

• ATP is the most important product of metabolism.

Skin Layers

• The layer below the dermis, containing blood vessels, is the subcutaneous layer.

Energy Sources

• Carbohydrate breakdown is the primary energy source, followed by lipid breakdown.

Glycolysis Product

• Glycolysis breaks down glucose into two 3-carbon molecules called pyruvic acid.

Skin Oil Glands

• Sebaceous glands produce oil to lubricate the skin.

Nervous System Functions

• Integrates sensory information
• Coordinates voluntary responses of many organ systems
• Monitors internal and external environments

Nervous System Impulse Types

• Afferent impulses carry information from the peripheral nervous system to the central nervous system.

Myelin Sheath

• A myelin sheath is a thin, membranous covering that increases the speed of action potentials along the axon.

Neuron Hyperpolarization

• Potassium ions cause neuron hyperpolarization.

Neuron Communication

• A neuron communicates with a muscle cell at a neuromuscular junction.

Meninges

• The dura mater is the outermost meningeal layer.

Neurotransmitters

• Excitatory: Glutamate (promotes signal transmission, learning, memory)
• Inhibitory: GABA (reduces activity, calms the brain)

Autonomic Nervous System Divisions

• Sympathetic: "Fight or flight". Receptors: adrenergic (alpha and beta)
• Parasympathetic: "Rest and digest". Receptors: cholinergic (muscarinic and nicotinic)

Non-Hormones

• Acetylcholine is not a hormone.

Hypothalamus Functions

• Releases ADH, oxytocin
• Secretes regulatory hormones for anterior pituitary
• Synthesizes ADH & oxytocin
• Controls adrenal medulla through sympathetic innervation

Hypothalamus Regulation

• Hypothalamic hormone secretion is regulated by negative feedback.

Hormone Definition

• A hormone is a chemical messenger released in one tissue and transported in the blood to target cells.

Cardiac Hormone

• Atrial natriuretic peptide is a heart hormone released during high atrial pressure.

Posterior Pituitary Hormones

• Antidiuretic Hormone (ADH): Reduces urine output, increases water reabsorption, maintains blood pressure and hydration
• Oxytocin: Stimulates uterine contractions during childbirth, promotes milk ejection, and plays a role in bonding/social behavior

Spermatogenesis Hormone

• FSH stimulates spermatogenesis.

Testosterone Hormone

• LH stimulates testosterone secretion in males.

Puberty Changes

• At puberty, levels of FSH and LH increase, and secondary sex characteristics appear. Oogenesis is also stimulated in females.

LH Alternative Names

• Luteinizing hormone (LH) was also called interstitial cell-stimulating hormone (ICSH) in males.

Respiratory System Entry Point

• Air enters the respiratory system through the nares (nostrils).

Shared Respiratory and Digestive System

• The pharynx is a chamber shared by the respiratory and digestive systems.

Mucus-Producing Cells

• Goblet cells produce mucus to trap particulate matter in the respiratory tract.

Laryngeal Opening

• The glottis is the narrow opening in the larynx that leads to the trachea.

Food/Liquid Prevention

• The epiglottis prevents food and liquid from entering the respiratory tract during swallowing.

Laryngeal Cartilages

• The thyroid cartilage sits superior to the cricoid cartilage in the larynx.

Vocal Cords

• The true vocal cords contain elastic ligaments extending between the thyroid and arytenoid cartilages.
• These cords vibrate to produce sound.

Gag/Cough Reflex

• The coughing reflex is triggered when the vocal cords are touched by food or liquid.

Trachea Structure

• The trachea contains C-shaped cartilages to maintain airway openness.

Bronchial Branches

• The trachea branches into right and left primary bronchi.

Bronchiolar Response to Nervous System

• Sympathetic: Bronchodilation (widening)
• Parasympathetic: Bronchoconstriction (narrowing/constricting)

Bronchiole Lead To

• Respiratory bronchioles lead to alveolar ducts and alveolar sacs.

Debris Removal Cells

• Alveolar macrophages patrol the respiratory epithelium and remove debris.

Alveoli Prevention Collapse

• Surfactant is an oily secretion that prevents alveoli from collapsing.

Pulmonary Blockage

• A pulmonary embolism is a blockage of a pulmonary artery branch.

Chest Wall Covering

• The parietal pleura covers the inner surface of the chest wall.

Small Blood Vessels

• Capillaries Connect the smallest arteries and veins.

Blood Vessel Layers

• The innermost layer of a blood vessel is the tunica interna (intima).

Blood Vessel Lumen Changes

• Vasodilation is relaxation of the arterial walls increasing the vessel diameter (lumen).
• Vasoconstriction is contraction of the arterial walls decreasing the vessel diameter.