Human Anatomy, Physiology, Homeostasis, Cellular Transport, and Histology Flashcards

Comprehensive review flashcards covering anatomy terminology, anatomical landmarks, homeostasis, feedback mechanisms, chemistry of ions, organic macromolecules, plasma membrane permeability, organelles, cellular transport, histology (epithelial and connective tissues), and organ membrane dynamics.

What standard body posture is shown here, and what three specific criteria define it?

Anatomical position, defined by: 1) Body erect, 2) Feet slightly apart, and 3) Palms facing forward.

When observing a patient or anatomical model, how do the subject's right and left correspond to the viewer's orientation?

The patient's right is the viewer's left, and the patient's left is the viewer's right.

What anatomical surface landmarks correspond to the front of the elbow, armpit, wrist, back of the knee, and heel of the foot?

Front of elbow: antecubital; Armpit: axillary; Wrist: carpal; Back of knee: popliteal; Heel of foot: calcaneal.

What is homeostasis, and what are the specific healthy set points for body temperature, blood pH, blood volume, blood pressure, and fasting blood glucose?

Homeostasis is the body's maintenance of a stable internal environment within a narrow range. Healthy set points: Body temperature $∱ 37\,^\circ\text{C}$ ($98\text{-}99\,^\circ\text{F}$), Blood pH $∱ 7.4$ ($7.35\text{-}7.45$), Blood volume $∱ 80\,\text{ml/kg}$ ($4\text{-}6\,\text{liters}$ total), Resting blood pressure $∱ 120/80\,\text{mmHg}$, and Fasting blood glucose $<100\,\text{mg/dL}$.

What defining operational rule distinguishes negative feedback mechanisms from positive feedback mechanisms?

In negative feedback loops, the physiological response opposes the initial stimulus to restore balance; in positive feedback mechanisms, the response enhances, amplifies, or promotes the stimulus until an outside event stops it.

How do baroreceptors and the cardiovascular integration center respond to elevated blood pressure in a negative feedback loop?

Baroreceptors detect high blood pressure (stimulus) and send signals to the integration center, which coordinates a response by decreasing heart rate and inducing vasodilation to lower blood pressure.

How does labor during childbirth function as a positive feedback mechanism, and what event terminates it?

Cervical stretch caused by the baby's head stimulates oxytocin release, which promotes stronger uterine contractions, increasing cervical stretch further; the cycle is terminated when the baby is delivered.

What is the structural difference between a cation and an anion, and why does a calcium ion carry a $\text{Ca}^{2+}$ designation?

A cation is a positively charged ion formed by losing electrons, whereas an anion is a negatively charged ion formed by gaining electrons. Calcium carries $\text{Ca}^{2+}$ because it has lost $2$ electrons, leaving it with $2$ more protons than electrons.

What roles do sodium ($\text{Na}^+$) and potassium ($\text{K}^+$) ions play in nervous system communication?

They diffuse across the neuronal plasma membrane down their concentration gradients to generate action potentials (electrical signals) that allow neurons to communicate.

What is glycogen, and where is it stored in the human body?

Glycogen is a carbohydrate polymer formed from joined glucose monomers; it serves as the storage form of glucose and is found in muscle and liver tissues.

How does the structure of phospholipids create a selectively permeable plasma membrane?

Phospholipids form a bilayer with hydrophilic (water-loving) phosphate heads facing outward toward the ECF and ICF, and hydrophobic (water-fearing) fatty acid tails facing inward toward each other, forming a barrier to water-soluble and charged substances.

In active carrier-mediated transport across the plasma membrane, how does the pump shown in this diagram utilize ATP?

It consumes energy from ATP hydrolysis to pump $3\,\text{Na}^+$ ions out of the cell and $2\,\text{K}^+$ ions into the cell against their respective concentration gradients.

What structural features determine whether a molecule can freely pass through the lipid bilayer without transport proteins?

Molecules that are small, non-polar, and lipid-soluble (such as $\text{O}_2$, $\text{CO}_2$, and steroids), as well as small uncharged molecules like $\text{H}_2\text{O}$, can diffuse freely down concentration gradients; large or charged molecules require transport proteins.

What are the primary roles of ribosomes, the endoplasmic reticulum, and the Golgi body in gene expression?

RNA produced in the nucleus is translated into amino acids/proteins by ribosomes on the endoplasmic reticulum; the Golgi body then packages these proteins into membranous vesicles for cell use or exocytosis.

What are the four major distinguishing characteristics of epithelial tissue?

1) Polarity (cells have distinct apical, lateral, and basal surfaces), 2) Attachment (cells attach to neighbors and a basement membrane), 3) Avascularity (no direct blood vessels), and 4) High regeneration capacity by stem cells.

According to this diagram of epithelial cell characteristics, what are the three distinct surfaces that define cell polarity?

1) Apical surface (unattached, facing the external environment or lumen), 2) Lateral surface (attached to neighboring epithelial cells), and 3) Basal/basolateral surface (anchored by the basement membrane to deep connective tissue).

What are the functional differences between microvilli and cilia on the apical surface of epithelial cells?

Microvilli are plasma membrane folds that increase surface area to maximize secretion and absorption; cilia are moveable protein projections that beat to move extracellular substances (like mucus) across the tissue surface.

What type of intercellular junction is depicted here, and what is its primary physiological role?

A gap junction; embedded connexon proteins form hollow cylinder channels between adjacent cells to promote direct diffusion of ions and small molecules for cellular communication.

How do tight junctions, desmosomes, and hemidesmosomes function in epithelial cell attachment?

Tight junctions prevent passage of solutes between lateral cell surfaces; desmosomes provide strong physical connections between adjacent lateral cells; hemidesmosomes attach the basolateral cell surface to the underlying basement membrane.

Because epithelial tissue is avascular, how do its cells obtain oxygen and nutrients and remove wastes?

Epithelial cells rely on diffusion of oxygen, nutrients, and wastes to and from blood vessels situated in the underlying loose (areolar) connective tissue.

How do simple squamous and simple cuboidal epithelia function differently within the kidney nephron?

Simple squamous epithelium forms the glomerulus capillaries to allow filtration of blood via diffusion; simple cuboidal epithelium lines the renal tubules to perform active reabsorption of nutrients and secretion of wastes.

What three basic components constitute all connective tissues, and what forms the matrix?

1) Specialized cells, 2) Protein fibers (collagen, elastic, reticular), and 3) Ground substance. The extracellular matrix is formed by the combination of ground substance and protein fibers.

What structural and functional features distinguish serous membranes from mucous membranes?

Serous membranes line sealed internal ventral cavities (secreting fluid to reduce friction around organs like the heart and lungs); mucous membranes line passageways open to the exterior environment (digestive, respiratory, urinary, reproductive) and produce protective mucus.

How do dense regular and dense irregular connective tissues differ in fiber arrangement and functional strength?

Dense regular CT contains parallel collagen fibers that resist tensile stress in one direction (found in tendons and ligaments); dense irregular CT contains an interwoven mesh of collagen fibers that resists multidirectional stress (found in the dermis and organ capsules).

What tissue layers compose the wall of the trachea from the lumen outward, and what are their functions?

1) Pseudostratified ciliated columnar epithelium with goblet cells (traps and sweeps debris), 2) Dense irregular connective tissue / lamina propria (anchors epithelium), 3) C-shaped hyaline cartilage rings (prevents airway collapse), 4) Trachealis smooth muscle (dilates/constricts airway), and 5) Areolar connective tissue / adventitia (protects and binds organ).