Question | Answer |
Homeostasis | Claude Bernard (1813-78)
stable internal conditions regardless of external conditions
Homeostasis
Walter Cannon (1871-1945) coined the term
fluctuates within limited range around a set point
Loss causes illness or death |
Negative Feedback Loop | Body senses a change and activates mechanisms to reverse it
Room temperature does not stay at set point of 68 degrees -- it only averages 68 degrees
Off 70 degrees
On 66 degrees |
Human Thermoregulation | Brain senses change in blood temperature
if overheating, vessels dilate in the skin and sweating begins
if too cold, vasoconstriction in the skin and shivering begins |
Control of Blood Pressure | Circulatory stretch receptors
detect a rise in BP
Cardiac center in brainstem
sends out nerve signals
Heart slowed and BP lowered |
Structure of Feedback Loop | Receptor = senses change
Integrator = control center that responds
Effector = structures that restore homeostasis |
Positive Feedback Loop | Self-amplifying change
leads to change in the same direction
Normal way of producing rapid changes
occurs with childbirth, blood clotting, protein digestion, and generation of nerve signals |
Life-THreatening Fever | Temperature > 108 degrees F
increases metabolic rate
body produces heat even faster
Cycle continues to reinforce itself
Becomes fatal at 113 degrees F |
7 Body Cavities | 1) Cranial cavity
2) Vetebral canal
3) Pleural cavities (2)
4) Pericardial cavity
5) Adominal cavity
6) Pelvic cavity |
Quadrants | Right Upper
Left Upper
Right Lower
Left Lower |
11 Organ Systems | 1) Integumentary
2) Skeletal
3) Muscular
4) Lymphatic
5) Respiratory
6) Urinary
7) Nervous
8) Endocrine
9) Circulatory
10) Digestive
11) Male/Female Reproductive |
9 Body Regions | 1) a R. Hypochondriac b Epigastric c L. Hypochondriac
2) a R. Lumbar b Umbilical c L. Lumbar
3) a R. Inguinal b Hypogastric c L. Inguinal |
Anterior landmarks | Cephallic
Facial
Cervical
Thoracic
Stern Pectoral
Umbilical
Abdominal
Inguinal
Pubic/External genitalia
Femoral
crural
Tarsal
Pedal
Dorsum
Plantar Surface
Acromial
Axillary
Brachial
Cubital
Antebrachial
Carpal
Palmar
Coxal
Patellar |
Posterior landmarks | Cranial
Nuchal
Interscapular
Scapular
Vertebral
Lumbar
Sacral
Gluteal
Dorsum of Hand
Perineal
Femoral
Popiteal
Crural
Tarsal
Calcaneal |
Membrane Transport | Plasma membrane selectively permeable
controls what enters or leaves cell
Passive transport requires no ATP
movement down concentration gradient
filtration and simple diffusion
Active transport requires ATP
movement against concentration gradient |
Filtration | Movement of particles through a selectively permeable membrane by hydrostatic pressure
Examples
filtration of nutrients from blood capillaries into tissue fluids
filtration of wastes from the blood in the kidneys |
Simple Diffusion | Net movement of particles from area of high concentration to area of low concentration
due to their constant, random motion
Also known as movement down the concentration gradient |
Membrane Permiability | Diffusion through lipid bilayer
Nonpolar, hydrophobic substances diffuse through lipid layer
Diffusion through channel proteins
water and charged hydrophilic solutes diffuse through channel proteins
Cells control permeability by regulating number of c |
Osmosis | Diffusion of water through a membrane
from area of more water to area of less water |
Osmotic Pressure | Amount of hydrostatic pressure required to stop osmosis
Osmosis slows due to filtration of water back across membrane due to inc hydrostatic pressure |
Osmolarity | One osmole = 1 mole of dissolved particles
Osmolarity = # osmoles/liter of solution |
Tonicity | Tonicity - ability of a solution to affect fluid volume and pressure within a cell
depends on concentration and permeability of solute |
Effects of Tonicity on RBCs | Hypotonic, isotonic and hypertonic solutions affect the fluid volume of a red blood cell. Notice the crenated and swollen cells. |
Carrier Mediated Transport | Proteins carry solutes across cell membrane
Specificity
solute binds to a specific receptor site on carrier protein
differs from membrane enzymes because solutes are unchanged
Types of carrier mediated transport
facilitated diffusion and active tra |
Membrane Carrier Saturation | Transport maximum = transport rate when all carriers are occupied |
Membrane Carriers | Uniporter: carries only one solute at a time
Symporter: carries 2 or more solutes simultaneously in same direction (cotransport)
Antiporter: 1. carries 2 or more solutes in opposite directions 2.sodium-potassium pump brings in K+ and removes Na |
Facilitated Diffusion | Transport of solute across membrane down its concentration gradient
No ATP used
Solute binds to carrier, it changes shape then releases solute on other side of membrane |
Active Transport | Transport of solute across membrane up (against) its concentration gradient
ATP energy required to change carrier
Examples:
sodium-potassium pump
bring amino acids into cell
pump Ca2+ out of cell |
Sodium Potassium Pump | Needed because Na+ and K+ constantly leak through membrane
half of daily calories utilized for pump
One ATP utilized to exchange three Na+ pushed out for two K+ brought in to cell |
Function of NA/K Pump | Regulation of cell volume
swelling stimulates the Na+- K+ pump to inc ion concentration, inc osmolarity and cell swelling
Heat production (thyroid hormone increase # of pumps; heat a by-product)
Maintenance of a membrane potential: inside -/outside + |
Vesicular Tramsport | Transport large particles or fluid droplets through membrane in vesicles
uses ATP
Exocytosis –transport out of cell
Endocytosis –transport into cell
phagocytosis – engulfing large particles
pinocytosis – taking in fluid droplets
receptor mediated e |
Phagocytosis | Keeps tissues free of debris and infectious microorganisms. |
Pinocytosis | Taking in droplets of ECF
occurs in all human cells
Membrane caves in, then pinches off into the cytoplasm as pinocytotic vesicle |
Trancytosis | Transport of a substance across a cell
Receptor mediated endocytosis moves it into cell and exocytosis moves it out the other side
ie insulin |
Receptor Mediated Endocytosis | Selective endocytosis
Receptor specificity
Clathrin-coated vesicle in cytoplasm
uptake of LDL from bloodstream |
Exocytosis | Secreting material or replacement of plasma membrane |
Histology | Study of Tissues
Epithelial Tissue
Connective Tissue
Nervous and Muscular Tissue
Intercellular Junctions, Glands and Membranes
Tissue Growth, Development, Death and Repair |
Epithelial Tissue | Layers of closely adhering cells
Flat sheet with upper surface exposed to the environment or an internal body cavity
No blood vessels
underlying connective tissue supplies oxygen
Rests on basement membrane
thin layer of collagen and adhesive proteins |
Simple Vs Stratified Epithelia | Simple epithelium
contains one layer of cells
named by shape of cells
Stratified epithelium
contains more than one layer
named by shape of apical cells |
Simple Squamous Epithelium | Single row of flat cells
Permits diffusion of substances
Secretes serous fluid
Alveoli, glomeruli, endothelium, and serosa |
Simple Cuboidal Epithelium | Single row cube-shaped cells with microvilli
Absorption and secretion, mucus production
Liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules |
Simple Columnar Epithelium | Single row tall, narrow cells
oval nuclei in basal half of cell
Absorption and secretion; mucus secretion
Lining of GI tract, uterus, kidney and uterine tubes |
Stratified Epithelium | More than one layer of cells
Named for shape of surface cells
exception is transitional epithelium
Deepest cells on basement membrane
Variations
keratinized epithelium has surface layer of dead cells
nonkeratinized epithelium lacks the layer of dea |
Keratinized Startified Squamous | Multilayered epithelium covered with dead squamous cells, packed with keratin
epidermal layer of skin
Retards water loss and barrier to organisms |
Nonkeratinized Stratified Squamous | Multilayered surface epithelium forming moist, slippery layer
Tongue, oral mucosa, esophagus and vagina |
Stratified Cuboidal Epithelium | Two or more cell layers; surface cells square
Secretes sweat; produces sperm and hormones
Sweat gland ducts; ovarian follicles and seminiferous tubules |
Transitional Epithelium | Multilayered epithelium surface cells that change from round to flat when stretched
allows for filling of urinary tract
ureter and bladder |
Connective Tissue | Widely spaced cells separated by fibers and ground substance
Most abundant and variable tissue type
Functions
connects organs
gives support and protection (physical and immune)
stores energy and produces heat
movement and transport of materials |
Fibroblasts | produce fibers and ground substance |
Collagen fibers | Collagen fibers (white fibers)
tough, stretch resistant, yet flexible
tendons, ligaments and deep layer of the skin |
Areolar Tissue | Loose arrangement of fibers and cells in abundant ground substance
Underlies all epithelia, between muscles, passageways for nerves and blood vessels |
Reticular Tissue | Loose network of reticular fibers and cells
Forms supportive stroma (framework) for lymphatic organs
Found in lymph nodes, spleen, thymus and bone marrow |
Adipose Tissue | Empty-looking cells with thin margins; nucleus pressed against cell membrane
Energy storage, insulation, cushioning
subcutaneous fat and organ packing
brown fat (hibernating animals) produces heat |
Dense Regular Connective Tissue | Densely, packed, parallel collagen fibers
compressed fibroblast nuclei
Tendons and ligaments hold bones together and attach muscles to bones |
Dense Irregular Connective Tissue | Densely packed, randomly arranged, collagen fibers and few visible cells
withstands stresses applied in different directions
deeper layer of skin; capsules around organs |
Cartilage | Supportive connective tissue with rubbery matrix
Chondroblasts produce matrix
called chondrocytes once surrounded
No blood vessels
diffusion brings nutrients and removes wastes
heals slowly
Types of cartilage: hyaline, fibrocartilage and elastic car |
Hyaline Cratilage | Rubbery matrix; dispersed collagen fibers; clustered chondrocytes in lacunae
supports airway, eases joint movements
Ends of bones at movable joints; sternal ends of ribs; supportive material in larynx, trachea, bronchi and fetal skeleton |
elastic Cartilage | Hyaline cartilage with elastic fibers
Provides flexible, elastic support
external ear and epiglottis |
Fribrocartilage | Hyaline cartilage with extensive collagen fibers (never has perichondrium)
Resists compression and absorbs shock
pubic symphysis, meniscus and intervertebral discs |
Bone | Spongy bone - spongy in appearance
delicate struts of bone
covered by compact bone
found in heads of long bones
Compact bone - solid in appearance
more complex arrangement
cells and matrix surround vertically oriented blood vessels in long bones |
Bone Tissue (compact bone) | Calcified matrix in lamellae around central canal
Osteocytes in lacunae between lamellae
Skeletal support; leverage for muscles; mineral storage |
Blood | Variety of cells and cell fragments; some with nuclei and some without
Nonnucleated pale pink cells or nucleated white blood cells
Found in heart and blood vessels |
Nerve tissue | Large cells with long cell processes
surrounded by smaller glial cells lacking processes
Internal communication between cells
in brain, spinal cord, nerves and ganglia |
Muscle Tissue | Elongated cells stimulated to contract
Exert physical force on other tissues
move limbs
push blood through a vessel
expel urine
Source of body heat
3 histological types of muscle
skeletal, cardiac and smooth |
Skeletal Muscle | Long, cylindrical, unbranched cells with striations and multiple peripheral nuclei
movement, facial expression, posture, breathing, speech, swallowing and excretion |
Cardiac Muscle | Short branched cells with striations and intercalated discs
one central nuclei per cell
Pumping of blood by cardiac (heart) muscle |
Smooth Muscle | Short fusiform cells; nonstriated with only one central nucleus
sheets of muscle in viscera; iris; hair follicles and sphincters
swallowing, GI tract functions, labor contractions, control of airflow, erection of hairs and control of pupil |
Diffusion Rates
Factors affecting diffusion rate through a membrane: | temperature - inc temp., inc motion of particles molecular weight - larger molecules move slower steepness of concentrated gradient - inc difference, inc rate membrane surface area - inc area, inc rate
membrane permeability - inc permeability, inc rate |
Hypotonic Solution | Hypotonic solution
low concentration of nonpermeating solutes (high water concentration)
cells absorb water, swell and may burst (lyse) |
Hypertonic Solution | Hypertonic solution
has high concentration of nonpermeating solutes (low water concentration)
cells lose water + shrivel (crenate)
*Hypoosmotic= less particles dissolved can be hypertonic |
Isotonic Solution | Isotonic solution = normal saline
*Hyperosmotic=more particles dissolved can be isotonic |
Secondary active transport | (No ATP used)
steep concentration gradient of Na+ and K+ maintained across the cell membrane
carriers move Na+ with 2nd solute easily into cell
SGLT saves glucose in kidney |
Pseudostratified Epithelium | Single row of cells some not reaching free surface
nuclei give layer stratified look
Secretes and propels respiratory mucus |
Macrophages | phagocytize foreign material and activate immune system
arise from monocytes (WBCs) |
Neutrophils | wander in search of bacteria |
Plasma cells | synthesize antibodies
arise from WBCs |
Mast cells | secrete
heparin inhibits clotting
histamine that dilates blood vessels |
Adipocytes | store triglycerides |
Reticular fibers | thin, collagen fibers coated with glycoprotein
framework in spleen and lymph nodes |
Elastic fibers | thin branching fibers of elastin protein
stretch and recoil like rubberband (elasticity)
skin, lungs and arteries stretch and recoil |
Gelatinous Material-Ground Substance | absorbs compressive forces |
Glycosaminoglycans-Ground Substance | chondroitin sulfate
disaccharides that attract sodium and hold water
role in regulating water and electrolyte balance |
Proteoglycan-Ground Substance | (bottlebrush-shaped molecule)
create bonds with cells or extracellular macromolecules |
Adhesive Glycoproteins-Ground Substance | protein-carbohydrate complexes bind cell membrane to collagen outside the cells |