Bio 255 Exam 1 Questions and Answers

Bio 255 Exam 1 Questions and Answers What are the two main cavities covered in lecture? Dorsal and ventral What is the function of the dorsal cavity and what two subdivisions does it contain? Protection of the nervous system; cranial cavity and vertebral cavity What is the function of the ventral cavity and what two subdivisions does it contain? Encloses internal organs; Thoracic (above diaphragm) and abdominopelvic What does the thoracic cavity contain? Pleural cavity, mediastinum (surrounds remaining organs), and pericardial cavity What does the abdominopelvic cavity contain? Abdominal cavity (stomach, intestines, spleen, liver) and pelvic cavity (bladder, reproductive organs, rectum) What kind of serous membrane lines the cavity wall? Parietal (remember serous membranes are continuous) What kind of serous membrane lines the organ it's associated with? Visceral (remember serous membranes are continuous) What is meant by the term "anatomical variability"? It means that humans vary slightly in their anatomy. Only about 90% of all anatomical structures match the textbook What are the functions of the plasma membrane? Physical boundary, separates intracellular fluids from extracellular fluids, transports molecules, enzymatic activity, signal transduction using receptors, intercellular adhesion, cell-cell recognition What is the structure of the plasma membrane? It is a phospholipid bilayer that has embedded proteins What is the difference between peripheral proteins and integral proteins in the plasma membrane? Peripheral - one side Integral - both sides What is the Glycocalyx and what is its function? Area around the cell composed of carbohydrates; provides highly specific biological markers for cell-cell recognition What are the four intracellular junctions? Tight, adhering, gap and desmosomes What are tight junctions? (stitches) Impermeable junction that encircles apical surface, inhibits movement between cells What are adhering junctions? (snaps) Junctions that provide apical support, deep to tight junction, resists separation of cells, composed of lots of desmosomes What are desmosomes? Anchoring junction scattered along the side of cells, joins cytoskeleton of cells together What are gap junctions? A channel that allows chemical substances to freely pass between the cytoplasm of two cells What is cytoplasm? All materials contained within the cell membrane and outside of the nucleus (cytosol, inclusions, organelles), it is the location of many metabolic reactions What is a cytoplasmic inclusion? Temporary storage for pigments, glycogen, and lipids; not in all cells and not enclosed What is the function of the smooth endoplasmic reticulum? Lipid synthesis & storage, carb metabolism, detox What is the function of the rough endoplasmic reticulum? Synthesis of exported proteins What is the function of the ribosomes? Synthesizing proteins, there are free ribosomes (make proteins for inside the cell) and fixed ribosomes (make exported proteins) What is the function of the golgi apparatus? Modify proteins, package proteins into secretory vesicles which can become lysosomes and undergo exocytosis or the can be incorporated into the plasma membrane What is the function of the lysosomes? They are vesicles with enzymes that digest waste products What is the function of peroxisomes? Vesicles with enzymes that breakdown special harmful substances (hydrogen peroxide, fatty acids, alcohol) What is the function of the mitochondria? ATP synthesis; cellular respiration What is the function of the centrosomes? Organizes and supports microtubule growth, directs formation of mitotic spindle during mitosis What is the function of the cytoskeleton and what does it contain? structural support and transport; microfilaments (maintain and change cell shape), intermediate filaments (structure/strength), and microtubules (gives shape to cell) What is the function of cilia? Moves substances along surfaces of cells via mucus What is the function of microvilli? Increase surface are to aid in absorption and secretion What is the function of the nucleus and what does it contain? Control center of cell (instructions for protein production); nucleolus and DNA What is and what is the function of the nucleolus? Areas of concentrated RNA, synthesis of ribosomal subunits How many pairs of chromosomes do humans have? 23, 22 autosomal, 1 sex What are the different levels of ploidy? Diploid (somatic cells), haploid (sex cells), and aneuploid (abnormal chromosome #) What is gene expression? Translating information in DNA (genotype) into functioning molecules (phenotype) What happens in interphase? Maintenance (resting) phase, replication of organelles and DNA occurs What are the phases within interphase? G1 phase - cell growth, replication of organelles and production of proteins S phase - synthesis phase where DNA replicates G2 phase - centriole replication is completed, enzymes needed for cell division are synthesized What happens in prophase? Chromatin supercoils to form chromosomes, sister chromatids join at the centromere, microtubules begin to form and centrioles migrate, nuclear envelope dissolves What happens in metaphase? Chromosomes line up along equatorial plate, spindle fibers attach to centromere forming the mitotic spindle What happens in anaphase? Spindle fibers pull sister chromatids apart to opposite ends of the cell What happens in telophase? A nuclear envelope reforms around each set of chromosomes, chromosomes uncoil and mitotic spindle disappears, cleavage begins to show and cytokinesis occurs What is cancer? Damaged DNA that leads to uncontrollable mitosis What is metastasis in regards to cancer? Cancer cells escape from original site How many checkpoints are there to prevent DNA damaging in interphase? 4 What are the four types of tissues? Epithelial, connective, muscular, and nervous What are the functions of epithelial tissues? Physical protection from dehydration or abrasion, selective permeability, secretion of mucus, enzymes, and hormones, and sensation of touch What are the characteristics of epithelial tissues? Composed of polar cells: - Apical surface to outside of covered structures or inside of lined structures, lateral surface to other cells, and basal surface to CT and basement membrane - Avascular; nutrients supplied by CT - Cells bound by tight junctions and desmosomes What is the function of simple squamous epithelial cells and where are they located? Lines structures, provides thin barrier for rapid diffusion; alveoli in lungs, amnion, kidneys Two kinds: Endothelium: lines blood vessels, heart and lymphatic vessels Mesothelium: found in serous membranes of ventral body cavity What is the function of simple cuboidal epithelial cells and where are they located? Lines cells, provides active barrier for secretion and absorption; ducts of glands, kidney tubules, ovary surface What is the function of simple columnar epithelial cells and where are they located? Absorption and secretion of mucus, ciliated types: movement of mucus; lining GI tract, some ducts of excretory glands, uterine tubes and part of uterus What is the function of pseudostratified columnar epithelial cells and where are they located? Secretion of mucus, movement of mucus; trachea, upper respiratory tracts and male reproductive ducts What is the function of stratified squamous epithelial cells and where are they located? Protection of tissue beneath from abrasion; skin, lining oral cavity, esophagus, and vagina What is the function of transitional epithelial cells and where are they located? Protects and stretches easily to hold fluid; bladder, ureters, urethra Where are stratified cuboidal and columnar epithelium located? Cuboidal - sweat, mammary, salivary glands Columnar - transition between two other epithelial types, male urethra, salivary glands What are the two ways you classify glandular epithelium? By morphology (unicellular, simple or compound, tubular or acinar) and by function (merocrine - releases contents via exocytosis, holocrine - cells rupture to release contents and apocrine - release apical surface) What is the function of areolar CT and what are some properties? Binds & cushions organs & skin; by volume, it is mostly viscous ground substance, highly vascularized, found beneath epithelia What is the function of adipose CT and what are some properties? Stores energy, cushions organs, prevents heat loss; only CT with more cells than matrix, found in hypodermic, near heart, kidneys, eyeballs, abdomen, breasts What is the function of reticular CT and what are some properties? Provides framework for organs; found in liver, spleen, lymph nodes, bone marrow What is the function of dense regular CT and what are some properties? Holds parts together; tightly packed collagen fibers with much strength against force in one direction, few blood vessels, makes up ligaments, tendons, and aponeuroses What is the function of dense irregular CT and what are some properties? Holds parts together; fibers run in several different directions which gives it strength in many directions, found in dermis, surrounding cartilage in bone What is the function of elastic CT and what are some properties? Allow stretch under force and recoil back to original strength; made up of branching elastic fibers and collagen fibers, found in vocal cords and walls of arteries What are some characteristics of cartilage? Avascular, no fibroblasts, mainly chondrocytes, chondrocytes sit in lacunae, firm gel-like extracellular matrix What is the function of hyaline cartilage and what are some properties? Flexible support; withstands stretch and compression, found in embryonic skeleton, articular cartilage, trachea, and larynx What is the function of fibrocartilage and what are some properties? Provides strength with minimal compression; many protein fibers, sparse ground substance, found in intervertebral discs and pubic symphysis What is the function of elastic cartilage and what are some properties? Extremely flexible support; lost of elastic fibers that are highly branched, found in epiglottis and external ear What is the function of blood? Transportation of nutrients, gases, and wastes; liquid matrix called plasma What is the function of bone and what is it made up of? Provides support and protection, blood cell production (hemopoiesis) and mineral storage; calcified matrix with collagen fibers What is the cutaneous membrane? Keratinized stratified squamous epithelium with dermis CT below What are mucous membranes? Lines body cavities that are connected to an external opening What are serous membranes? Lines body cavities and secretes serous fluid What are synovial membranes? Lines joint cavities and secretes synovial fluid; consists of areolar, fibrous or adipose CT What are some characteristics of skeletal muscle? Cells are: - Cylindrical and long - Multinucleated - Striated - Voluntary; contracted by somatic nervous system What are some characteristics of cardiac muscle? Cells are: - Branched and shorter than skeletal - Striated - One or two nuclei per cell - Involuntary - Attached at the ends by intercalated discs - Contain gap junctions that allow rapid passage of current between cells during each heart beat What are some characteristics of smooth muscle? Cells are: - Short and fusiform - Non-striated - One nucleus per cell - Involuntary What makes up nervous tissues and what are their functions? Neurons - detect stimuli and send nerve impulses Neuroglia - protect and support neurons What are the five periods from gamete to birth? Prenatal Period - from fertilization until birth ~ 38 weeks Zygote - fertilized cell Blastocyst - 0-2nd week; spherical multicellular structure that develops from zygote Embryo - 3-8th week, germ cell layers form, most organs and physical feature appear Fetus - 9th week-birth; growth and development of organs What is gametogenesis? Production of sperm/ovum via meiosis How many chromosomes does a zygote have when a sperm fertilizes an ovum? 46 (23 pairs) What happens in Meiosis I? Diploid parent cell produces two haploid daughter cells What happens in Meiosis II? Sister chromatids of each chromosome separate and go into different daughter cells What is sperm capacitation? Breakdown of glycoprotein coat, allows sperm to locate oocyte and break down oocyte protect layers with enzymes; sperm MUST undergo this before penetration of oocyte What happens when the sperm makes contact with the membrane of an oocyte? Sperm binds with binding receptor proteins on oocyte membrane, sperm's pronucleus enters ovum, oocyte complete meiosis II What two components are formed during pre-embryonic development and how long does it take? Trophoblasts - single, outer ring of cells from placenta Embryoblasts - Inner cell mass that will form embryonic disc 2 weeks What happens in implantation? Trophoblasts adheres to uterine wall, trophoblast cells proliferate, form 2 layers: Cytotrophoblast - inner cellular layer Syncytiotrophoblast - outer layer, cells lost plasma membrane How is the bilaminar germinal disc formed? Embryoblast differentiates into 2 layers: Hypoblast - adjacent to blastocyst cavity Epiblast - adjacent to trophoblast What are the extraembryonic membranes and when are they formed? Yolk sac, amnion, chorion; week 2 How is the yolk sac formed? Hypoblast cells form sac on ventral surface of embryo How is the amnion formed? Epiblast cells form transparent membrane filled sac with amniotic fluid What is the chorion? Outermost membrane formed by cytochondroblasts What is the placenta and what does it do? Highly vascularized organ that serves as a physical and biochemical interface between embryo and mother; exchange of nutrients, waste products, and respiratory gases, production of hormones, transmission of antibodies