Updated bio 2

What is anatomy?

Study of organism structure.

What is physiology?

Study of how organisms and their parts function.

What is homeostasis?

Maintenance of a relatively stable internal environment.

What are the levels of organization above cells?

Tissue → organ → organ system → organism.

What is a tissue?

A group of similar cells working together for a specialized function.

What is an organ?

A structure made of two or more tissues that performs a specific function.

What is an organ system?

A group of organs working together for a major body function.

What are the four basic animal tissue types?

Epithelial, connective, muscle, nervous.

What do anchoring junctions do?

Weld cells together, especially in stretch-prone tissues.

What do tight junctions do?

Seal spaces between cells and prevent leakage.

What do gap junctions do?

Allow ions and small molecules to pass directly between cells.

What is epithelial tissue?

Sheet-like layers of closely connected cells with little ECM.

Apical vs basal surface?

Apical = free surface; basal = surface attached to underlying tissue.

Cilia vs microvilli?

Cilia move fluid; microvilli increase surface area.

Simple vs stratified epithelium?

Simple = one layer; stratified = multiple layers.

Squamous vs cuboidal vs columnar?

Flat vs cube-shaped vs tall/elongated cells.

Simple squamous epithelium: location + function?

Blood vessels/lung air sacs; diffusion.

Stratified squamous epithelium: location + function?

Skin, mouth, esophagus, vagina; protection from abrasion.

Cuboidal epithelium: location + function?

Glands/kidney tubules; secretion and absorption.

Columnar epithelium: location + function?

Gut/respiratory lining; secretion and absorption.

Exocrine vs endocrine gland?

Exocrine uses a duct; endocrine releases hormones into ECF/blood.

What is connective tissue mainly characterized by?

Cells separated by extracellular matrix.

What determines connective tissue properties?

Type and amount of extracellular matrix.

Collagen, fibronectin, elastin: roles?

Collagen = strength; fibronectin = attachment; elastin = recoil.

Loose connective tissue: main roles?

Supports epithelia, surrounds vessels/nerves, forms mesenteries.

Dense connective tissue: features + examples?

Parallel collagen/elastin for strength; tendons, ligaments, cornea.

Cartilage: cells + functions?

Chondrocytes; support, flexibility, compression resistance.

Osteoblasts vs osteoclasts?

Osteoblasts build bone; osteoclasts break it down.

What is an osteon?

Structural unit of compact bone with a central canal and concentric layers.

Blood: plasma, erythrocytes, leukocytes, platelets?

Fluid matrix; RBCs carry O2; WBCs defend; platelets clot.

What are the three muscle types?

Skeletal, cardiac, smooth.

Skeletal muscle: key features?

Striated, multinucleate, voluntary, attached to skeleton.

Cardiac muscle: key features?

Striated, involuntary, branched, intercalated discs.

Smooth muscle: key features?

Nonstriated, spindle-shaped, involuntary, in hollow organs.

Neuron parts and directions?

Dendrites receive; axon sends; cell body integrates.

ECF vs ICF?

ECF = outside cells; ICF = inside cells.

Regulator vs conformer?

Regulator keeps internal conditions stable; conformer changes with environment.

Local vs systemic homeostatic control?

Local acts within an organ; systemic uses nervous/endocrine control.

Negative feedback pathway?

Stimulus → sensor → integrator → effector → compensatory response.

Positive feedback example?

Childbirth: contractions → oxytocin → stronger contractions.

What is a hormone?

A regulatory chemical released into ECF and carried by blood.

Classical endocrine vs neurohormone signaling?

Endocrine = gland to blood; neurohormone = neuron to blood.

Paracrine vs autocrine signaling?

Paracrine acts nearby; autocrine acts on the same cell.

What are the four hormone classes?

Amine, peptide, steroid, fatty acid-derived.

Most amine hormones: key traits?

Usually hydrophilic, tyrosine-based, bind cell-surface receptors.

Important amine exception?

Thyroxine is hydrophobic and binds intracellular receptors.

Peptide hormones: key traits?

Amino acid chains; commonly water-soluble.

Steroid hormones: key traits?

Cholesterol-derived, hydrophobic, carrier-bound, intracellular receptors.

Example of fatty acid-derived hormones?

Prostaglandins.

What do prostaglandins do?

Local regulation of smooth muscle, pain, and inflammation.

Lipophilic vs hydrophilic hormones?

Lipophilic use carriers/intracellular receptors; hydrophilic use surface receptors.

What do extracellular receptors use?

Second messengers.

What determines whether a cell responds to a hormone?

Presence of the appropriate receptor.

Endocrine vs exocrine?

Endocrine secretes into ECF/blood; exocrine secretes into ducts.

What is another name for the pituitary gland?

Hypophysis.

Where is the pituitary located?

It hangs by a stalk from the hypothalamus.

Two pituitary divisions?

Anterior pituitary and posterior pituitary.

Anterior pituitary hormones listed in the slides?

TSH, ACTH, MSH, GH, PRL, FSH, LH, endorphins.

What is a tropic hormone?

A hormone that acts on another endocrine gland.

GH: main effects?

Stimulates cell division, protein synthesis, and growth.

Prolactin: main effect?

Stimulates mammary development and milk synthesis.

MSH and endorphins: main effects?

MSH increases melanin; endorphins help control pain.

ADH: main effect?

Increases kidney water reabsorption and blood volume.

Oxytocin: main effects?

Milk ejection and stronger uterine contractions.

Major endocrine glands/tissues besides hypothalamus/pituitary?

Thyroid, parathyroids, adrenal medulla/cortex, gonads, pancreas, pineal.

What hormones does the thyroid secrete?

T4, T3, calcitonin.

T4 vs T3?

T4 is a precursor; T3 is more active.

What does calcitonin do?

Lowers blood Ca2+ by promoting uptake into bone.

What does PTH do overall?

Raises blood Ca2+.

How does PTH raise blood Ca2+?

Bone release, kidney reabsorption, vitamin D activation.

Adrenal medulla: stimulus + hormones?

Sympathetic nervous system; epinephrine and norepinephrine.

Adrenal cortex: stimulus + hormones?

ACTH; corticosteroids such as cortisol and aldosterone.

Cortisol vs aldosterone?

Cortisol supports glucose/stress response; aldosterone regulates minerals.

Which pancreatic cells secrete insulin?

Beta cells.

What does insulin do?

Lowers blood glucose by promoting uptake and storage.

Which pancreatic cells secrete glucagon?

Alpha cells.

What does glucagon do?

Raises blood glucose by mobilizing stored fuels.

Type I vs Type II diabetes in the slides?

Type I lacks insulin-secreting beta cells; Type II has reduced insulin responsiveness.

What does the pineal gland secrete and when?

Melatonin, especially in darkness.

What does melatonin regulate?

Circadian rhythms.

Asexual vs sexual reproduction?

Asexual uses one parent; sexual involves fusion of egg and sperm.

Main advantage of asexual reproduction?

Low energy cost and preservation of successful genotypes.

Main advantage of sexual reproduction?

Greater genetic diversity.

Fission, budding, fragmentation?

Split into offspring; outgrowth from parent; pieces regenerate.

What is parthenogenesis?

Development from an unfertilized egg.

Why are parthenogenetic offspring not always identical?

The egg is produced by meiosis.

What creates genetic diversity in sexual reproduction?

Recombination, independent assortment, random fertilization, mutation.

What is gametogenesis?

Formation of gametes.

What is fertilization?

Fusion of egg and sperm.

What does fertilization produce?

A diploid zygote.

What are germ cells?

Cells that give rise to gametes.

What are gonads?

Testes in males and ovaries in females.

Spermatogenesis result?

Four mature haploid sperm.

Oogenesis result?

One mature haploid ovum plus polar bodies.

Why does the ovum keep most cytoplasm?

To retain nutrients and molecules for early development.

Where are oocytes arrested before ovulation?

Prophase I.

Where is the secondary oocyte arrested at ovulation?

Metaphase II.

When does the oocyte complete meiosis?

After fertilization.

Main sperm structures + functions?

Acrosome penetrates egg; nucleus has DNA; mitochondria make ATP; flagellum moves.

External vs internal fertilization?

External occurs outside body; internal occurs in female reproductive tract.