HLCR 100 Unit

Primary functions of the skeletal system

Structural framework, lever system for movement, soft-tissue protection, mineral storage (calcium and phosphorus), and hematopoiesis

What is hematopoiesis?

Blood cell generation within red marrow

Part of the axial skeleton

Skull, hyoid, vertebral column, ribs, sternum, frontal, pariental, temporal, occipital, sphenoid, ethmoid, zygomatic, maxilla, nasal, lacrimal, and mandible

Part of the appendicular skeleton

Clavicle, scapula, humerus, radius, ulna, carpals, metacarpals, phalanges, Ilium, Ischium, pubis, femur, tibia, fibula, tarsals, metatarsals

Synovial joints

feature hyaline articular cartilage, a synovial membrane producing lubricating fluid, ligaments (connecting bone to bone), and bursae (fluid-filled friction-reducing sacs)

Arthritis

Joint inflammation (osteoarthritis - A degenerative "wear and tear" disease where the protective cartilage cushioning the ends of the bones gradually breaks down over time. vs. rheumatoid arthritis An autoimmune disease where the immune system mistakenly attacks the synovium (the lining of the joints), causing chronic inflammation and joint damage.)

Fractures

Disruption in bone continuity.

Scoliosis

Lateral curvature

Kyphosis

Excessive thoracic curvature, hunchback

Lordosis

Excessive lumbar curvature, swayback

Masseter and Temporalis

Mandibular elevation

Sternocleidomastoid

Head rotation, flexion

Pectoralis Major

Arm adduction, medial rotation

Pectoralis Minor

Scapular protraction

Trapezius

Scapular elevation, depression, retraction

Rhomboids

Scapular retraction

Latissimus Dorsi

Arm extension, adduction

Erector Spinae

Spinal extension

Rectus Abdominis

Longitudinal muscles in the abdomen, flexion of the trunk

External obliques

Fibers run medially, flexion, rotation of the trunk

Internal Obliques

Fibers run laterally, flexion, rotation of the trunk

Transversus Abdominis

Fibers run straight across, compression of the abdomen

Deltoid

Arm abduction, flexion, extension

Biceps Brachii

Elbow flexion, forearm supination

Triceps Brachii

Elbow extension

Gluteus Maximus

Hip extension

Quadriceps

Knee extension

Hamstrings

Knee flexion

Adductors

Hip adduction

Gastrocnemius/Soleus

Ankle plantarflexion

Contractures

Permanent muscle shortening

Fibromyalgia

Widespread musculoskeletal pain

Gangrene

Bacterial necrosis via Clostridium

Muscular Dystrophy

Progressive genetic muscle loss

Sprains

Ligament damage

Strains

Muscle/tendon injury

Central Nervous System (CNS)

Brain and spinal cord, Protected by the cranium and vertebral column, meninges (dura mater, arachnoid mater, pia mater), and circulating cerebrospinal fluid (CSF)

Peripheral Nervous System (PNS)

12 pairs of cranial nerves and 31 pairs of spinal nerves.

Somatic Nervous System

Controls voluntary skeletal muscle movements and sensory transmission.

Autonomic Nervous System (ANS)

Involuntary visceral regulation.

Sympathetic Division

“Flight-or-fight” response (elevates heart rate, dilates bronchioles, redistributes blood flow to skeletal muscle, suppresses peristalsis)

Parasympathetic Division

“Rest-and-digest” response (lowers heart rate, constricts bronchioles, stimulates digestive motility and secretions)

Frontal Lobe

Executive function

Parietal Lobe

Sensation

Temporal Lobe

Auditory processing

Occipital Lobe

Visual processing

Cerebellum

Motor coordination/learning

Brainstem

Vital functions like breathing and heart rate

Dendrites

Receive incoming signals

Cell Body (soma)

Central, bulbous part of a neuron that contains the cell nucleus and powers the cells life support and function

Axon

Transmits action potentials away

Myelin sheath

Accelerates conduction along white matter.

Synaptic gaps

These are crossed by neurotransmitters.

Cerebrovascular Accident (CVA/Stroke)

Ischemic or hemorrhagic disruption of cerebral blood supply causing hemiplegia and aphasia.

Transient Ischemic Attack (TIA)

Brief focal neurological deficit serving as a stroke warning.

Amyotrophic Lateral Sclerosis (ALS)

Progressive degeneration of motor neurons leading to paralysis.

Parkinson’s Disease

Loss of dopamine-producing neurons in the substantia nigra causing tremors, rigidity, and a shuffling gait.

Multiple Sclerosis (MS)

Autoimmune demyelination of CNS nerve fibers.

Epilepsy

Recurrent seizure activity caused by abnormal electrical discharges.

Endocrine System

Chemical messengers (hormones) are released into bloodstream to act on target organs.

Hypothalamus and Pituitary Gland

Master regulatory center controlling Growth Hormone (GH), TSH, ACTH, FSH, LH, Prolactin, ADH and Oxytocin via feedback loops.

Thyroid Gland

Secretes T3, T4 (metabolic rate), and Calcitonin. Regulates metabolic rate and energy levels.

Pancreas

Produce insulin (lowers blood glucose), and glucagon (elevates blood glucose).

Adrenal Cortex

Secretes cortisol and aldosterone

Adrenal Medulla

Secretes epinephrine and norepinephrine

Gonads

Ovaries (estrogen, progesterone) and Testes (testosterone)

Addison’s disease

Hyposecretion of cortisol

Cushing’s syndrome

Hypersecretion of cortisol causing moon face and buffalo hump

Diabetes Mellitus

Impaired insulin production/sensitivity leading to hyperglycemia, polyuria, polydipsia, and polyphagia

Gigantism and Acromegaly

Excessive growth hormone

Urinary System

Two kidneys, two ureters, urinary bladder, and urethra

Nephron Function

The structural and functional unit of the kidney. Filters blood and the glomerulus inside Bowman’s capsule, reabsorbs essential nutrients, and excretes metabolic wastes to regulate fluid balance, blood pressure, and pH.

Pathologies of the Urinary System

Polycystic Kidney Disease (PKD), Urinary Tract Infections (UTIs)

Lymphatic System

Drains excess fluid from capillary beds, filters pathogens, maintains fluid volume, and coordinates immune responses.

Anatomical Components of the Lymphatic System

Lymphatic vessels, lymph nodes, spleen, and thymus gland

Pathologies of the Lymphatic System

Lymphedema (fluid accumulation secondary to lymphatic obstruction) and Tonsillitis.

P Wave

Atrial depolarization

QRS Complex

Ventricular depolarization (masks atrial repolarization)

T Wave

Ventricular repolarization

Atrial Fibrillation

Chaotic atrial activity; generally non-lethal immediately

Ventricular Fibrillation

V-fib; fatal emergency requiring immediate defibrillation

Median Cubital

Standard venipuncture site

Saphenous

Great Saphenous is the longest vein in the human body

Nasal Cavity

Warms, filters, humidifies air

Pharynx

Nasopharynx, oropharynx, and laryngopharynx

Epiglottis

Prevents aspiration

Larynx

Vocal folds

Inhalation

Diaphragm contracts and moves downward, expanding thoracic volume and decreasing intrapulmonary pressure below atmospheric levels

Exhalation

Diaphragm relaxes and move upward, decreasing thoracic volume and elevating intrapulmonary pressure to expel air

Atelectasis

Alveolar collapse

Chronic Obstructive Pulmonary Disease

COPD; includes chronic bronchitis and emphysema

Pneumothorax

Air in the pleural cavity causing lung collapse

Mouth

Salivary amylase breakdown

Esophagus

Peristaltic propulsive movements

Stomach

Hydrochloric acid and pepsin digestion

Small Intestine

Duodenum, Jejunum, Ileum; nutrient absorption via microvilli

Large Intestine

Water/electrolyte absorption. Vitamin K synthesis by gut microbiota

Liver

Produces bile (emulsifies fats), neutralizes toxins, stores glycogen, and synthesizes clotting factors (prothrombin)

Gallbladder

Stores and concentrates bile

Pancreas

Secretes digestive enzymes (lipases, proteases, amylases) and bicarbonate into the duodenum