Biology 2401 Lecture Exam 2 Review: Integumentary, Skeletal, and Muscular Systems

Comprehensive vocabulary flashcards covering the Integumentary, Skeletal, and Muscular systems based on Biology 2401 lecture notes.

Stratum corneum

The most superficial epidermal layer consisting of dead, flat keratinocytes filled with keratin that protect against abrasion, penetration, and water loss.

Stratum lucidum

A clear, dead layer of the epidermis found only in thick skin like the palms and soles; it provides an extra layer of protection and water resistance.

Stratum granulosum

The layer where keratinocytes flatten and accumulate keratohyalin and lamellar granules to initiate keratinization and waterproof the skin using glycolipids.

Stratum spinosum

The spiny layer that provides strength and flexibility, resists tension with desmosomes, and contains immune Langerhans (dendritic) cells.

Stratum basale

The deepest single row of stem cells that are actively dividing; it contains melanocytes for UV protection and Merkel cells for touch.

Sebaceous activity in puberty

Increased androgens stimulate oil glands to produce excess sebum, leading to blocked pores, inflammation, and acne.

Epidermis

The superficial layer of the skin composed of stratified squamous epithelium; it is avascular, meaning it contains no blood vessels.

Dermis

The deep layer of the skin consisting of dense irregular connective tissue; it is highly vascular and houses glands and hair.

Hypodermis

Also known as subcutaneous tissue, it is not part of the skin but consist of adipose tissue that anchors the skin to muscle.

Dermal vasoconstriction

The mechanism where blood vessels in the dermis constrict to redirect warm blood to vital organs when a person is cold, causing the skin to look pale.

Long bones

Bones that are longer than they are wide, such as the femur, humerus, and phalanges.

Short bones

Cube-shaped bones, with examples including the carpals and tarsals.

Flat bones

Thin, flattened, and slightly curved bones such as the sternum, ribs, and skull bones.

Irregular bones

Bones with complicated shapes, for example, the vertebrae and hip bones.

Sesamoid bones

Short bones formed within tendons, such as the patella.

Compact bone

Bone tissue adapted to support weight and withstand torsion (twisting forces).

Spongy bone

Bone tissue adapted to resist forces from multiple directions and lighten the skeleton.

Red bone marrow

Contains hematopoietic tissue and stem cells that produce red and white blood cells and platelets; most abundant in cavities of spongy bone within flat bones and the heads of long bones.

Yellow bone marrow

Contains adipose tissue such as stored triglycerides and fat.

Osteogenic cells

Mitotic stem cells that differentiate into osteoblasts.

Osteoblasts

Bone-building cells that secrete the unmineralized bone matrix known as osteoid.

Osteocytes

Mature bone cells that watch and keep the bone matrix.

Osteoclasts

Bone-resorbing cells that dissolve bone matrix using acids and lysosomal enzymes to release calcium.

Embryonic skeleton tissues

Consists of hyaline cartilage for endochondral ossification and fibrous membranes for intramembranous ossification.

Rickets

Vitamin D or calcium deficiency in children characterized by soft, bowed bones.

Osteomalacia

Vitamin D or calcium deficiency in adults resulting in poorly mineralized, painful bones.

Osteoporosis

A condition where bone resorption outpaces bone deposition, causing bone density to drop drastically while the matrix remains normal.

Paget’s Disease

Haphazard, excessive bone remodeling leading to weak, deformed bones and abnormally high spongy-to-compact bone ratios.

Epiphyseal plate

A layer of cartilage that stops dividing at the end of adolescence, around ages $18$ to $21$, and is replaced by bone to leave an epiphyseal line.

Diaphysis

The tubular shaft that forms along the long axis of a bone and contains the medullary cavity.

Epiphysis

The proximal and distal ends of a bone which are filled with spongy bone.

Periosteum

A double-layered outer membrane that anchors tendons and ligaments and houses bone cells.

Endosteum

The internal membrane lining canals and trabeculae; it is active in bone remodeling.

Articular Cartilage

Hyaline cartilage covering epiphyseal surfaces that acts as a shock absorber and reduces friction to allow joints to glide easily.

Fibrocartilage

Tough, shock-absorbing cartilage that resists high pressure; found in the pubic symphysis, intervertebral discs, and knee menisci.

Hyaline Cartilage

Smooth, glassy, and slippery cartilage that allows frictionless movement; found in synovial joints, rib connections (costal cartilage), and growth plates.

Skeletal growth hormones

During infancy and childhood, Growth Hormone (GH) released by the anterior pituitary and thyroid hormones regulate growth.

Wolff’s Law

The principle that bone grows or remodels in direct response to mechanical demands, stresses, and forces; heavier loading results in thicker, denser bone.

Parathyroid Hormone (PTH)

A hormone released by the parathyroid glands when blood calcium drops; it signals bones to release calcium and kidneys and intestines to absorb more.

Fibrous Joints

Immovable joints where bones are held tightly by tough fibers, such as skull sutures and tooth roots.

Cartilaginous Joints

Joints connected by cartilage that allow very little movement and act as shock absorbers, such as intervertebral discs.

Synovial Joints

Freely movable joints filled with fluid to help bones glide, such as the shoulders and hips.

Meniscus

Two wedge-shaped pieces of rubbery cartilage between the femur and tibia that act as shock absorbers in the knee.

Ligaments

Tough bands of tissue that connect bone to bone and provide stability.

Bursae

Tiny, fluid-filled sacs that act as a cushion and lubricant between bones and moving soft tissues.

Synarthrosis

Immovable joints that lock bones together tightly for protection, such as those in the head.

Amphiarthrosis

Slightly movable joints connected by tough cartilage, such as those between spinal vertebrae.

Diarthrosis

Freely movable joints, which are the most common type of joint in the body.

Tendon sheaths

Protective, fluid-filled tubes that act as slippery sleeves around tendons.

Patellar ligament

The ligament responsible for the knee jerk reflex.

Gout

Painful joint swelling caused by uric acid crystals; treated with anti-inflammatory drugs (colchicine, steroids, NSAIDs) and allopurinol for long-term prevention.

Lyme Disease

A bacterial infection transmitted by tick bites; treated with a $10$ to $14$-day course of oral antibiotics like doxycycline or amoxicillin.

Osteoarthritis

Wear and tear on protective cartilage at bone ends; treated with acetaminophen, NSAIDs, or steroid injections.

Tropomyosin

A protein that acts as a physical barrier in muscle cells by covering attachment sites on actin filaments to prevent myosin from connecting.

Skeletal Muscle

Voluntary, striated muscle with many nuclei attached to bones to move the skeleton and generate heat.

Cardiac Muscle

Involuntary, striated muscle found only in the heart wall with branched cells connected by intercalated discs used to pump blood.

Smooth Muscle

Involuntary, non-striated, spindle-shaped muscle found in the walls of hollow internal organs that moves substances and regulates blood pressure.

Muscle recruitment

The process of activating more motor units to increase physical strength.

Slow Oxidative (SO) Fibers

Type I slow-twitch fibers that use oxygen (aerobic), have very high endurance, are red in color, and are best for long-distance tasks.

Fast Oxidative (FO) Fibers

Type IIa fast-twitch fibers that use oxygen but can switch to anaerobic metabolism; they have medium endurance and are pink to light red.

Fast Glycolytic (FG) Fibers

Type IIx/IIb fast-twitch fibers that use sugar without oxygen (anaerobic), have the fastest contraction speed but low endurance, and are white.

Sarcomere

The basic functional unit of a muscle that allows for contraction and relaxation.

Z-Discs

The boundaries at both ends of the sarcomere that anchor thin filaments and connect adjacent sarcomeres.

Actin

Thin protein filaments in a sarcomere attached to Z-Discs that extend toward the center.

Myosin

Thick protein filaments in the center of the sarcomere with "heads" that grab onto actin.

A-Band

The dark central area of a sarcomere that spans the entire length of the thick filaments and stays the same length during contraction.

Muscle calcium

Acts as an "on switch" for movement by binding to troponin, which moves tropomyosin to expose binding sites on actin.

Myasthenia gravis

An autoimmune disease where the body destroys its own ACh receptors at the neuromuscular junction, leading to muscle weakness.

Curare

A plant poison that blocks ACh receptors, causing flaccid paralysis and death via respiratory failure.

Myofibrils

These make up $80\%$ of muscle fibers and provide the ability to generate physical force and produce movement.

Voltage-gated sodium channel

The protein in muscle most associated with excitability.

Acetylcholinesterase

A specific enzyme that instantly breaks down the acetylcholine (ACh) molecule to stop its effect on the motor end plate.

Hemoglobin

The oxygen-binding molecule found in the blood.

Myoglobin

The oxygen-binding molecule found in the muscle.

Rigor mortis

Stiffening of the body after death caused by the depletion of ATP, which is needed for muscles to relax.

What is the result in puberty of increased sebaceous activity

Increased androgens stimulate sebaceous (oil) glands to produce excess sebum. Blocked pores lead to inflammation, resulting in acne.

Know the epidermal layers in order from superficial (surface) to deep (base):

Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale, (Epidermis, Dermis, Hypodermis)

Why does the skin gets pale in a person who is very cold and pale?

Dermal blood vessels constrict (vasoconstriction) to redirect warm blood to vital organs. Reduced blood flow to the skin surface causes the skin to look pale.

What does red bone marrow contain?

Contains hematopoietic tissue, including stem cells that produce red and white blood cells and platelets.

What does yellow bone marrow contain?

Has adipose tissue such as stored triglycerides/fat).

What are the types of tissue that all bone types are in an embryo before they turn into bone?

Before bone formation, the embryonic skeleton consists of hyaline cartilage, for endochondral ossification, and fibrous membranes, for intramembranous ossification)

Know what type of bones have the most abundant red bone marrow, and be able to give an example.

Red marrow is most abundant in the cavities of spongy bone within flat bones and the heads of long bones; for example: the sternum or the ilium/hip bone

Know what the epiphyseal plate is and when it disappears

At the end of adolescence, around ages 18–21, the cartilage stops dividing and is entirely replaced by bone, leaving behind an epiphyseal line.

Know how the epiphyseal plate grows

Cartilage cells (chondrocytes) on the epiphyseal side rapidly undergo mitosis (proliferation zone). Older chondrocytes hypertrophy, die, and the matrix calcifies. Osteoblasts then replace the dead cartilage with new bone on the diaphyseal side.

What can prevent osteoporosis?

Adequate calcium/Vitamin D intake, weight-bearing exercise, and avoiding smoking.

Which hormones are most responsible growth during infancy and childhood.

Growth Hormone (GH), which is released by the anterior pituitary gland, and thyroid hormones are most responsible for regulating skeletal growth.

What is the negative feedback mechanism for restoring calcium levels in the blood?

When your blood calcium drops, the parathyroid glands detect it and release PTH (parathyroid hormone). This hormone signals your bones to release stored calcium, your kidneys to absorb more calcium before it's lost in urine, and your intestines to absorb more from food.

What makes an individual double jointed?

Their joints bend further than normal.

Know the terms used to describe motion in a joint.

Pivot, bend, or rotate.

The ligament responsible for the knee jerk reflex.

Patellar ligament.

What is Gout?

Painful joint swelling caused by uric acid crystals.

How to treat Gout?

Flare-up treatments: Prescription anti-inflammatory drugs like colchicine, steroids, or NSAIDs to stop immediate pain.

Long-term treatments: Daily uric-acid-lowering medications (like allopurinol) to prevent future attacks.

Lifestyle habits: Drink plenty of water and limit alcohol (especially beer), red meat, and high-fructose foods.

What is Lyme Disease?

A bacterial infection transmitted by tick bites.

How to treat Lyme Disease?

Treatments: A 10 to 14-day course of prescribed oral antibiotics (like doxycycline or amoxicillin). Early treatment usually cures the infection. 

Aftercare: Do not use continuous antibiotics for lingering aches after the initial infection clears, as research shows they are not effective

What is Osteoarthritis?

Wear and tear on the protective cartilage at the ends of bones.

How to treat Osteoarthritis?

Treatments: Pain relievers, such as acetaminophen, or oral/gel NSAIDs (like ibuprofen). Doctors may also inject steroids directly into the joint for temporary pain relief

Lifestyle habits: Maintain a healthy weight and engage in low-impact exercises (like swimming or walking) to reduce joint stress