Chapters 1, 3, 4, 5 | University of Florida
Difficulty: Foundational | Prerequisites: None (this is your starting point)
Tags: anatomy, physiology, homeostasis, cells, tissues, integumentary system, EXER 2168, UF, health professions, body orientation, skin, cell transport, tissue types
Module 1 lays the groundwork for every system you will study this semester. It starts with how the body is organised (Chapter 1), moves into the cell as the basic unit of life (Chapter 3), then zooms out to how cells form tissues (Chapter 4), and finishes with the integumentary system as your first complete organ system (Chapter 5). If you do not have these foundations down cold, every later module will feel harder than it needs to be. The language, directional terms, and feedback concepts from Chapter 1 reappear in every exam question for the rest of the course.
The human body is organised from atoms up to organ systems, maintained by homeostatic feedback loops. Cells are the structural and functional units of life, bounded by a selectively permeable membrane, and they group into four tissue types. The integumentary system (skin) is the body's largest organ and your first case study in how structure meets function.
Tags: structural hierarchy, homeostasis, negative feedback, positive feedback, anatomical position, body planes, directional terms, abdominopelvic regions, organ systems
Anatomy
The study of the structure of body parts and their relationships to one another. In simple terms, anatomy is about what things look like and where they sit.
Physiology
The study of the function of body parts, how they work individually and together. Think of it as the "why does it do that?" side of the coin.
Structural hierarchy (levels of organisation)
Chemical → cellular → tissue → organ → organ system → organismal. Each level builds on the one below it. A useful mnemonic: "Can Cells Talk? Only Occasionally, Obviously."
Homeostasis
The body's ability to maintain a relatively stable internal environment despite changes in external conditions. Think of it as the body's thermostat, constantly adjusting to keep everything within a narrow, functional range.
Negative feedback mechanism
A control mechanism that reduces or reverses a change, bringing the body back toward a set point. Most homeostatic mechanisms in the body are negative feedback. Example: rising blood glucose triggers insulin release, which lowers blood glucose back to normal.
Positive feedback mechanism
A control mechanism that amplifies or increases a change, pushing the body further from the starting point. These are rarer and usually self-limiting. Example: during childbirth, oxytocin increases uterine contractions, which causes more oxytocin release, which causes stronger contractions, until delivery occurs.
Anatomical position
The standard reference position: body upright, feet shoulder-width apart, palms facing forward, thumbs pointing away from the body. Every directional term assumes the body is in this position, even if the patient is lying down.
Directional terms
Superior (cranial): toward the head
Inferior (caudal): toward the feet
Anterior (ventral): toward the front
Posterior (dorsal): toward the back
Medial: toward the midline
Lateral: away from the midline
Proximal: closer to the trunk or point of attachment
Distal: farther from the trunk or point of attachment
Superficial: toward the surface
Deep: away from the surface
Body planes
Sagittal: divides left and right (midsagittal = equal halves)
Frontal (coronal): divides anterior and posterior
Transverse (horizontal/cross-sectional): divides superior and inferior
Abdominopelvic regions
Nine regions: right/left hypochondriac, epigastric, right/left lumbar, umbilical, right/left iliac (inguinal), hypogastric. Alternatively, four quadrants: RUQ, LUQ, RLQ, LLQ. Clinicians often use quadrants; textbooks use nine regions for more precision.
The body must maintain eight necessary life functions: maintaining boundaries, movement, responsiveness (irritability), digestion, metabolism, excretion, reproduction, and growth.
Survival needs include nutrients, oxygen, water, appropriate temperature, and atmospheric pressure. Remove any one of these for long enough and homeostasis fails.
Every homeostatic control mechanism has three components:
Receptor: detects a change (stimulus) in the environment
Control centre (integrator): determines the set point and analyses the input, then sends output commands
Effector: carries out the response to reduce or amplify the stimulus
Negative feedback is the dominant pattern. Positive feedback is used in situations where a rapid, escalating response is needed (blood clotting, childbirth, protein digestion in the stomach via pepsinogen activation).
There are 11 organ systems. For the exam, know each system's major organs and primary function:
Integumentary: skin, hair, nails; protection, temperature regulation
Skeletal: bones, cartilage; support, protection, blood cell formation
Muscular: skeletal muscles; movement, posture, heat production
Nervous: brain, spinal cord, nerves; fast-acting control, sensory input
Endocrine: glands (pituitary, thyroid, adrenals, etc.); slow-acting chemical control via hormones
Cardiovascular: heart, blood vessels; transport of blood
Lymphatic/Immune: lymph nodes, spleen; immunity, fluid return
Respiratory: lungs, airways; gas exchange
Digestive: stomach, intestines, liver; nutrient breakdown and absorption
Urinary: kidneys, bladder; waste removal, water/electrolyte balance
Reproductive: ovaries/testes; production of offspring
Students often confuse negative feedback with something "bad." Negative here means the response opposes the stimulus. It is the body's main way of staying balanced.
Positive feedback is not the same as "good feedback." It means the response amplifies the stimulus. It can be dangerous if unchecked (e.g., fever spiralling out of control).
Anatomical position has palms facing forward. Many students forget this and mislabel medial/lateral on the forearm.
Superior/inferior apply only when comparing structures within the same body, not between different people.
⚠️ You will be asked to identify structures using directional terms. Practise by describing the position of one structure relative to another (e.g., "the sternum is medial to the clavicle and anterior to the vertebral column").
⚠️ Know the difference between the nine-region and four-quadrant systems for the abdominopelvic cavity. Be able to assign organs to their correct region/quadrant.
⚠️ Positive vs. negative feedback is a favourite exam topic. Be ready to identify which type a given scenario describes and name the receptor, control centre, and effector.
True or False: The heart is superior to the diaphragm. (True)
Fill in the blank: A _______ plane divides the body into anterior and posterior portions. (Frontal/coronal)
True or False: Positive feedback mechanisms are the body's primary homeostatic control. (False, negative feedback is primary)
Fill in the blank: The wrist is _______ to the elbow. (Distal)
True or False: The epigastric region sits below the umbilical region. (False, it sits above)
Tags: cell theory, plasma membrane, phospholipid bilayer, membrane transport, diffusion, osmosis, tonicity, active transport, vesicular transport, organelles, cell cycle, mitosis, DNA, RNA, nucleus
Cell theory
All living things are composed of cells, cells are the basic structural and functional units of life, and all cells arise from pre-existing cells.
Plasma membrane
The flexible outer boundary of the cell, composed of a phospholipid bilayer with embedded proteins. Think of it as a selective gatekeeper: it decides what enters and leaves the cell.
Phospholipid bilayer
Two layers of phospholipid molecules arranged with hydrophilic (water-loving) heads facing outward and hydrophobic (water-fearing) tails facing inward. This arrangement makes the membrane selectively permeable.
Integral proteins
Proteins embedded within the lipid bilayer, often spanning its entire thickness (transmembrane proteins). They serve as channels, carriers, receptors, and enzymes.
Peripheral proteins
Proteins loosely attached to the inner or outer surface of the membrane. They often function as enzymes or in cell signalling.
Cell junctions
Tight junctions: seal neighbouring cells together so nothing leaks between them (like cling film between tiles)
Desmosomes: rivets that anchor cells together but allow substances to pass between them
Gap junctions: small channels that allow direct chemical communication between cells (like a tiny doorway)
Diffusion
The movement of molecules from an area of higher concentration to an area of lower concentration. No energy required. Think of it as a drop of ink spreading through water on its own.
Facilitated diffusion
Diffusion that requires a membrane protein (channel or carrier) to help molecules cross. Still passive, still follows the concentration gradient, just needs a doorman.
Osmosis
The diffusion of water across a selectively permeable membrane, moving toward the area of higher solute concentration. Water chases the solute.
Tonicity
The ability of a solution to cause a cell to gain or lose water.
Isotonic: solute concentration equal inside and outside, no net water movement
Hypertonic: higher solute outside, cell loses water and crenates (shrivels)
Hypotonic: lower solute outside, cell gains water and may lyse (burst)
Active transport
The movement of substances against their concentration gradient, requiring ATP. The cell's energy-burning freight lift.
Vesicular transport
Movement of large particles or volumes of fluid into or out of the cell via membrane-bound vesicles.
Endocytosis: substances enter the cell (phagocytosis for solids, pinocytosis for fluids, receptor-mediated endocytosis for specific molecules)
Exocytosis: substances leave the cell
Membrane potential
The voltage difference across the plasma membrane, typically around -70 mV in a resting cell. The inside of the cell is more negative relative to the outside. This electrical charge is essential for nerve and muscle function.
Cytoplasm
All cellular material between the plasma membrane and the nucleus, including the cytosol (gel-like fluid) and organelles.
Organelles (key ones to know)
Mitochondria: ATP production ("powerhouses of the cell")
Ribosomes: protein synthesis
Rough endoplasmic reticulum (RER): protein synthesis and modification (studded with ribosomes)
Smooth endoplasmic reticulum (SER): lipid synthesis, detoxification, calcium storage
Golgi apparatus: packages, modifies, and ships proteins
Lysosomes: intracellular digestion (contain hydrolytic enzymes)
Peroxisomes: detoxify harmful substances, break down fatty acids
Cytoskeleton: microfilaments, intermediate filaments, microtubules; structural support and cell movement
Centrioles: organise microtubules during cell division
Cilia and flagella: cell surface projections for movement
Nucleus
The cell's control centre, containing DNA. Bounded by a double membrane (nuclear envelope) with nuclear pores. Contains chromatin (loosely coiled DNA), which condenses into chromosomes during division. The nucleolus within is the site of ribosomal RNA production.
Cell cycle
The sequence of events from one cell division to the next. Consists of interphase (G1, S, G2) and the mitotic phase (mitosis + cytokinesis).
G1: cell growth, normal metabolic activity
S: DNA replication
G2: preparation for division
Mitosis: division of the nucleus (prophase, metaphase, anaphase, telophase)
Cytokinesis: division of the cytoplasm
RNA (ribonucleic acid)
mRNA (messenger RNA): carries the genetic code from DNA to ribosomes
tRNA (transfer RNA): brings amino acids to the ribosome during translation
rRNA (ribosomal RNA): structural component of ribosomes
Feature | Passive Transport | Active Transport |
|---|---|---|
Energy required? | No | Yes (ATP) |
Direction | Down concentration gradient | Against concentration gradient |
Examples | Diffusion, osmosis, facilitated diffusion | Sodium-potassium pump, vesicular transport |
The Na⁺/K⁺ ATPase pumps 3 Na⁺ out and 2 K⁺ in per cycle, using one ATP. This maintains the resting membrane potential and the concentration gradients essential for nerve impulse transmission.
DNA → (transcription) → mRNA → (translation) → Protein. Transcription occurs in the nucleus; translation occurs at ribosomes in the cytoplasm. This is the pathway by which genes direct cell activity.
Tonicity is why an IV drip must be isotonic (e.g., normal saline, 0.9% NaCl). A hypotonic IV would cause red blood cells to swell and burst; a hypertonic IV would cause them to shrivel.
Cystic fibrosis is caused by a defective chloride channel protein in the plasma membrane, showing how a single membrane protein malfunction can cause systemic disease.
Students often think osmosis moves water toward the "weaker" solution. Water moves toward higher solute concentration (i.e., the more concentrated side pulls water in).
Facilitated diffusion is still passive. The presence of a protein helper does not make it active; what matters is whether ATP is used and the direction relative to the gradient.
Mitosis produces two identical diploid daughter cells. Meiosis (not covered in this chapter) produces four haploid cells. Do not confuse the two.
The cell membrane is not rigid. The fluid mosaic model means proteins float and drift within the bilayer.
⚠️ Be able to predict what happens to a cell placed in isotonic, hypertonic, and hypotonic solutions.
⚠️ Know the difference between passive and active transport and be able to classify any given example.
⚠️ Understand the phases of the cell cycle and what happens in each. Expect questions asking you to place events in order.
⚠️ Know the major organelles and their functions. Matching questions are common.
True or False: Facilitated diffusion requires ATP. (False)
Fill in the blank: In a hypertonic solution, a red blood cell will _______. (Crenate/shrivel)
True or False: The Golgi apparatus is where proteins are first synthesised. (False, ribosomes/RER synthesise proteins; the Golgi packages and ships them)
Fill in the blank: DNA replication occurs during the _______ phase of interphase. (S phase)
True or False: Gap junctions allow direct communication between adjacent cells. (True)
Tags: epithelial tissue, connective tissue, muscle tissue, nervous tissue, tissue repair, germ layers, membranes, basement membrane, collagen, extracellular matrix
Tissue
A group of cells that are similar in structure and work together to perform a specific function. There are four primary tissue types.
Epithelial tissue (epithelium)
Covers body surfaces, lines hollow organs and cavities, and forms glands. Cells sit on a basement membrane, are tightly packed with minimal extracellular matrix, and are avascular (receive nutrients by diffusion from underlying connective tissue).
Classification is by number of layers and cell shape:
Layers: simple (one layer), stratified (multiple layers), pseudostratified (appears layered but is not)
Shape: squamous (flat), cuboidal (cube-shaped), columnar (tall, column-like)
Transitional epithelium: stretchy, found in the urinary bladder
Connective tissue
The most abundant and widely distributed tissue type. Characterised by cells separated by large amounts of extracellular matrix (ground substance + fibres). Most types are well vascularised (cartilage is the notable exception).
Major types:
Connective tissue proper: loose (areolar, adipose, reticular) and dense (regular, irregular, elastic)
Cartilage: hyaline, elastic, fibrocartilage
Bone (osseous tissue)
Blood (liquid connective tissue)
Extracellular matrix (ECM)
The material between connective tissue cells. Composed of ground substance (water, glycosaminoglycans, proteoglycans) and protein fibres (collagen, elastic, reticular).
Muscle tissue
Produces movement through contraction. Three types:
Skeletal: voluntary, striated, multinucleated
Cardiac: involuntary, striated, branching cells with intercalated discs
Smooth: involuntary, non-striated, found in walls of hollow organs
Nervous tissue
Composed of neurons (conduct impulses) and neuroglia (support cells). Found in the brain, spinal cord, and nerves.
Membranes
Cutaneous membrane: skin (dry membrane)
Mucous membranes: line body cavities open to the exterior (respiratory, digestive, urogenital tracts); secrete mucus
Serous membranes: line closed body cavities (pleura, pericardium, peritoneum); secrete thin serous fluid to reduce friction
Synovial membranes: line joint cavities; secrete synovial fluid
Tissue repair
The body repairs damaged tissue through regeneration (replacement with the same type of cell) or fibrosis (replacement with scar tissue). The process involves inflammation, organisation, and regeneration/fibrosis. Tissues with high mitotic rates (epithelial, bone, blood-forming) regenerate well. Cardiac muscle and nervous tissue regenerate poorly.
Germ layers
Three primary germ layers form during embryonic development:
Ectoderm: gives rise to nervous tissue and epidermis
Mesoderm: gives rise to muscle, bone, connective tissue, cardiovascular system
Endoderm: gives rise to the linings of the digestive and respiratory tracts
Simple squamous: thin, single layer, ideal for diffusion and filtration (alveoli, capillary walls, serous membranes)
Simple cuboidal: secretion and absorption (kidney tubules, small glands)
Simple columnar: absorption and secretion, often with goblet cells (digestive tract lining)
Pseudostratified columnar: appears multilayered, often ciliated (trachea, upper respiratory tract)
Stratified squamous: multiple layers, protects against abrasion (skin, mouth, oesophagus, vagina)
Transitional: stretches to accommodate distension (urinary bladder, ureters)
Collagen fibres: strong, resist tension (like steel cables)
Elastic fibres: stretch and recoil (like rubber bands)
Reticular fibres: thin, form a supporting mesh (like scaffolding)
Understanding tissue types is essential for interpreting biopsies. A pathologist identifies disease by examining which tissue is present, how cells look, and whether tissue architecture is normal. Cancer is fundamentally a problem of tissue gone wrong: cells that have lost normal control of division and differentiation.
Students often forget that cartilage is avascular. This is why cartilage injuries heal so slowly.
"Stratified" does not mean "better." It means multiple layers, which provides protection against mechanical abrasion but is not needed where diffusion or absorption is the goal.
Not all connective tissues look alike. Blood is a connective tissue, as is bone. The definition hinges on having cells dispersed in an extracellular matrix, not on how "firm" or "soft" the tissue looks.
Cardiac muscle is striated like skeletal muscle, but it is involuntary. Do not equate "striated" with "voluntary."
⚠️ Be able to identify tissue types from a description or image. Expect questions that describe a location and ask you to name the tissue found there.
⚠️ Know the three germ layers and what each gives rise to.
⚠️ Understand why some tissues regenerate well (epithelial) and others do not (cardiac muscle, neurons).
⚠️ Know the four types of body membranes, where each is found, and what it secretes.
True or False: Epithelial tissue has a rich blood supply. (False, it is avascular)
Fill in the blank: The three types of muscle tissue are skeletal, cardiac, and _______. (Smooth)
True or False: Blood is classified as a connective tissue. (True)
Fill in the blank: The germ layer that gives rise to the nervous system is the _______. (Ectoderm)
True or False: Serous membranes line body cavities that open to the exterior. (False, they line closed cavities; mucous membranes line cavities open to the exterior)
Tags: skin, epidermis, dermis, hypodermis, keratinocytes, melanocytes, skin colour, hair, nails, sweat glands, sebaceous glands, skin cancer, burns, integument
Integumentary system
The skin and its derivatives (hair, nails, glands). The skin is the body's largest organ.
Epidermis
The outermost layer of skin. Composed of stratified squamous epithelium. Avascular. Contains four main cell types and (in thick skin) five named layers.
Cell types:
Keratinocytes: the most abundant cells; produce keratin, the tough protective protein
Melanocytes: produce melanin, the pigment that protects against UV radiation
Dendritic (Langerhans) cells: immune cells that detect and present foreign substances
Merkel (tactile) cells: sensory receptors for touch
Layers of the epidermis (from deep to superficial):
Stratum basale (basal layer): single row of actively dividing stem cells; where melanocytes reside
Stratum spinosum (spiny layer): several layers of keratinocytes; Langerhans cells most abundant here
Stratum granulosum (granular layer): 3 to 5 layers; cells begin producing keratohyaline and lamellated granules
Stratum lucidum (clear layer): present only in thick skin (palms, soles); thin translucent band
Stratum corneum (horny layer): 20 to 30 layers of dead, flattened, keratinised cells; the outermost protective barrier
A mnemonic for the layers from deep to superficial: "Brits Sip Gin, Luckily Conscientiously" (Basale, Spinosum, Granulosum, Lucidum, Corneum).
Dermis
The deeper, thicker layer of skin beneath the epidermis. Composed of strong, flexible connective tissue. Contains blood vessels, nerve endings, glands, and hair follicles. Two layers:
Papillary layer: thin, superficial, areolar connective tissue with dermal papillae (create fingerprints); contains capillaries that nourish the epidermis
Reticular layer: deep, thick, dense irregular connective tissue; provides strength and stretch
Hypodermis (subcutaneous layer / superficial fascia)
Not technically part of the skin, but anchors skin to underlying structures. Composed mostly of adipose tissue. Absorbs shock, insulates, and stores energy.
Cleavage (tension) lines
Lines of tension in the skin caused by the orientation of collagen fibres in the dermis. Surgical incisions made parallel to cleavage lines heal better and produce less scarring.
Flexure lines
Creases on the skin surface at joints where the dermis is tightly bound to deeper structures (e.g., wrist creases, finger joints).
Skin colour pigments
Three pigments contribute:
Melanin: brown/black (eumelanin) or reddish-yellow (pheomelanin); produced by melanocytes and transferred to keratinocytes; everyone has roughly the same number of melanocytes, but the amount and type of melanin produced varies
Carotene: yellow-orange pigment from diet, accumulates in the stratum corneum and hypodermis
Haemoglobin: gives oxygenated blood its red colour, visible through light skin in areas with many capillaries
Skin colour changes (clinical significance)
Cyanosis (bluish): low oxygenation of haemoglobin
Erythema (redness): increased blood flow (fever, inflammation, embarrassment)
Pallor (paleness): decreased blood flow or low haemoglobin (anaemia, shock, fear)
Jaundice (yellow): excess bilirubin in the blood (liver disorder)
Bruising (black/blue/purple): escaped blood clotting beneath the skin
Hair
Composed of keratinised cells. Grows from a hair follicle, which is an invagination of the epidermis into the dermis. The hair bulb at the base contains the matrix (actively dividing cells). The arrector pili muscle attaches to each follicle and contracts to produce "goosebumps."
Nails
Scale-like modifications of the epidermis. The nail body (visible portion) covers the nail bed. Growth occurs at the nail matrix beneath the proximal nail fold. The white crescent at the base is the lunula.
Sweat glands (sudoriferous glands)
Eccrine (merocrine): found nearly everywhere, open directly onto the skin surface, produce watery sweat for thermoregulation
Apocrine: found in axillary and anogenital areas, empty into hair follicles, produce a thicker secretion that becomes odorous when acted on by bacteria
Sebaceous (oil) glands
Found everywhere except palms and soles. Secrete sebum (an oily substance) into hair follicles to soften skin and hair and help prevent water loss. Blocked sebaceous glands produce acne.
Skin performs several critical functions:
Protection: physical barrier against pathogens, UV radiation, chemical damage, and water loss
Temperature regulation: via sweat production, vasodilation (release heat), and vasoconstriction (conserve heat)
Cutaneous sensation: receptors for touch, pressure, pain, temperature
Metabolic functions: synthesis of vitamin D when UV light strikes the skin
Blood reservoir: the dermis holds up to 5% of total blood volume
Excretion: small amounts of nitrogen-containing wastes eliminated in sweat
Three main types:
Basal cell carcinoma: most common, least dangerous, arises from stratum basale, rarely metastasises
Squamous cell carcinoma: arises from keratinocytes of stratum spinosum, can metastasise if untreated
Melanoma: arises from melanocytes, least common but most dangerous, high tendency to metastasise. Use the ABCDE rule for identification: Asymmetry, Border irregularity, Colour variation, Diameter greater than 6 mm, Evolution (changing over time)
Classified by depth:
First-degree (superficial): epidermis only, red and painful (sunburn)
Second-degree (partial thickness): epidermis and upper dermis, blisters form, very painful
Third-degree (full thickness): destroys epidermis and dermis, may extend into hypodermis, nerve endings destroyed so area itself is painless (though edges are painful)
The Rule of Nines estimates the percentage of body surface area burned: head = 9%, each arm = 9%, each leg = 18%, anterior trunk = 18%, posterior trunk = 18%, perineum = 1%.
Understanding cleavage lines is directly relevant to surgical practice. A surgeon who makes an incision along a cleavage line will produce a thinner scar that heals more cleanly than one made across the lines. Skin grafting for burn victims relies on the regenerative capacity of the stratum basale; if this layer is destroyed (third-degree burns), grafting from an uninjured site is necessary.
Students often think darker-skinned people have more melanocytes. They do not. Everyone has roughly the same number of melanocytes; the difference is in the amount, type, and distribution of melanin produced.
The hypodermis is not part of the skin. It lies deep to the dermis and is sometimes called the subcutaneous layer.
Third-degree burns are not always the most painful at the burn site, because nerve endings in the dermis are destroyed. Pain is felt at the edges where second-degree damage occurs.
Eccrine sweat glands are the ones primarily responsible for thermoregulation, not apocrine glands.
⚠️ Know the layers of the epidermis in order, from deep to superficial, and what happens in each layer.
⚠️ Be able to differentiate the two dermal layers and their tissue types.
⚠️ The three pigments contributing to skin colour and the clinical significance of colour changes are commonly tested.
⚠️ Know the ABCDE rule for melanoma and the classification of burns by depth.
⚠️ The Rule of Nines is a favourite calculation question.
True or False: The stratum lucidum is found in all skin. (False, only thick skin)
Fill in the blank: The pigment responsible for the yellow-orange colour in skin is _______. (Carotene)
True or False: Sebaceous glands are most active during childhood. (False, they become most active during puberty and adolescence)
Fill in the blank: Using the Rule of Nines, both legs account for _______% of body surface area. (36%)
True or False: Melanoma arises from keratinocytes. (False, it arises from melanocytes)
Q: A patient is found to have a blood glucose level well above normal. The pancreas releases insulin, which causes cells to absorb glucose, lowering blood glucose levels. What type of feedback mechanism is this?
A: Negative feedback. The response (insulin release lowering blood glucose) opposes the original stimulus (high blood glucose).
Q: A cell is placed in a solution where the solute concentration outside the cell is higher than inside. What will happen to the cell?
A: Water will leave the cell by osmosis, moving toward the higher solute concentration. The cell will shrink (crenate). This is a hypertonic solution.
Q: Name the four primary tissue types and give one distinguishing feature of each.
A: Epithelial (covers surfaces, avascular), connective (most abundant, cells in extracellular matrix), muscle (contracts to produce movement), nervous (conducts electrical impulses).
Q: Which epidermal layer contains actively dividing stem cells?
A: The stratum basale.
Q: A patient presents with yellowish skin and eyes. What condition does this suggest, and what substance is responsible?
A: Jaundice, caused by excess bilirubin in the blood, typically indicating a liver disorder.
Q: What is the functional difference between tight junctions and gap junctions?
A: Tight junctions create a watertight seal between cells, preventing substances from leaking between them. Gap junctions form small channels that allow direct passage of ions and small molecules between adjacent cells.
Q: Compare and contrast eccrine and apocrine sweat glands.
A: Eccrine glands are found nearly everywhere on the body, open onto the skin surface, and produce watery sweat primarily for temperature regulation. Apocrine glands are found mainly in the axillary and anogenital regions, empty into hair follicles, and produce a thicker secretion that becomes odorous when broken down by skin bacteria.
Q: A surgeon must make an incision on a patient's abdomen. Why should she consider cleavage lines when planning her incision?
A: Cleavage lines indicate the predominant direction of collagen fibres in the dermis. An incision made parallel to these lines will gape less, heal faster, and produce less scar tissue than one made across them.
The homeostatic mechanisms introduced in Chapter 1 reappear in every system you will study. Negative feedback controls blood calcium levels (Chapter 6, skeletal system), blood pressure (cardiovascular, later courses), and body temperature (integumentary, Chapter 5 + nervous system). The cell biology from Chapter 3 is the foundation for understanding how muscle cells contract (Chapter 9), how neurons fire action potentials (Chapter 11), and why membrane potential matters. The four tissue types from Chapter 4 appear in every organ you dissect: recognising them under a microscope is a skill that carries through the entire course.
Anatomy and physiology study guide, EXER 2168 UF, A&P 1 final exam review, homeostasis definition, negative feedback loop anatomy, positive feedback examples, anatomical position directional terms, body planes sagittal frontal transverse, cell membrane structure, phospholipid bilayer, osmosis diffusion active transport, tonicity isotonic hypertonic hypotonic, cell organelles functions, mitosis cell cycle phases, four tissue types, epithelial tissue classification, connective tissue types, germ layers ectoderm mesoderm endoderm, skin layers epidermis dermis, stratum basale corneum, melanin keratin, ABCDE melanoma rule, Rule of Nines burns, sweat glands sebaceous glands