A&P Midterm 1

transverse plane

horizontal division of the body into upper and lower portions

sagittal plane

divides body into left and right. can be perfectly split down middle or may be more cut on lateral portions

Midsagittal (median) plane

divides the body into right and left sides perfectly down middle

coronal plane

divides body into front and back

oblique plane

passes through the body at an angle

anatomical direction

see image

Fossa

shallow depression in a bone

Foramen

Round or oval opening through a bone

fissure

an opening; a groove; a split

fenestration

perforation

anatomical position

To stand erect with arms at the sides and palms of the hands turned forward, head facing forward

dorsal body cavity

contains the cranial cavity and spinal column (CNS)

ventral body cavity

thoracic and abdominopelvic cavities

Two types of serous membranes

parietal and visceral

parietal layer

lines the internal surface of the body wall

visceral layer

covers external surface of organs

what exists in between the parietal and visceral layers of the serous membranes?

fluid acting as surfactant to reduce friction

cytology

study of cells/structure

cell physiology

study of cellular function

scanning electron microscope

3-D, study of surface features

transmission electron microscope

2-D, internal structures of a cell or within organelle

Benefits of electron microscopes

allow you to view organelles such as mitochondria, nucleus, ribosomes ,etc... this is not possible with a light microscope

Which organelles lack membranes?

ribosomes, centrosome/centriole, cilia/flagella, cytoskeleton, nucleolus

Which organelles have two lipid bilayer membranes?

Mitochondria, nucleus

Which organelles have one lipid bilayer?

lysosomes, peroxisomes, ER, golgi, plasma membrane

what do nuclear pores on the nuclear envelope do?

allows molecules to pass between the nucleus and cytoplasm

Are there any membrane bound organelles in the nucleus?

No. nucleolus is not membrane bound, neither are ribosomes

What does the nucleus contain?

DNA and chromosomes

What is the function of the nucleus?

stores and transmits genetic information

Where does translation (mRNA to amino acid) occur?

cytoplasm

Nucleoulus

the area in the nucleus of a cell where ribosomes are produced

Ribosomes

site of protein synthesis

Two types of ribosomes

free ribosomes (cytosol) membrane-bound ribosomes(rough ER- synthesize protein needed for export or for use within the cell membrane)

Endoplasmic Reticulum

A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.

Smooth ER

no ribosomes, synthesizes phospholipids, steroids, and fats

-detoxifies harmful substances like alcohol

Rough ER

contains ribosomes, synthesize and package proteins for export from the cell (continuous with nuclear envelope)

Golgi apparatus

flattened stack of tubular membranes that modifies, sorts, and packages proteins into vesicles and transports them to other organelles or out of the cell

Golgi function

Modifies, sorts, and packages proteins

Lysosomes

filled with digestive enzymes, acidic environment

What do lysosomes do?

digest foreign substances, or digest/recycle components of organelles.

Peroxisomes

vesicles containing enzymes that oxidize toxic organic material

Mitochondira

Double membrane,, inner forms cristea, matrix center, forms ATP, contains own DNA, reproduces independently

Cytosol

The semifluid portion of the cytoplasm (55% of cell volume. 75-90% water)

What takes place in cytosol?

glycolysis, ATP production, gluconeogenesis

cytokeleton

protein filaments throughout cytosol that provide support and gives cell shape

Microfilaments (actin filaments)

Long, thin fibers that function in the movement and support of the cell

intermediate filaments

anchor organelles

Microtubules (tubulin)

flagella, cilia, centrosome

Centrosome function

formation of cilia and flagella basal bodies and development of mitotic spindle

cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Flegella

Long structure "tail"-like to propel, like sperm

components of cell membrane

phospholipids, cholesterol, proteins, carbohydrates

what is the cell membrane?

flexible but sturdy barrier that surround cytoplasm in the cell

phospholipids in the cell membrane

amphipathic (polar heads, non polar tails)

cholesterol in cell membrane

helps stabilize the membrane fluidity, cell rigidity

proteins in cell membrane

integral and peripheral.

integral proteins

extend into the cell membrane

peripheral proteins

bound to the surface of the membrane

function of integral proteins

channels, receptors, interaction with extracellular matrix.

Glycocalyx

The external surface of a plasma membrane that is important for cell-to-cell communication

in the eye: allows for tear film adherence

transmembrane proteins

specific channels for small and medium sized polar and charged particles

lipid bilayer is permeable to

nonpolar, uncharged molecules including oxygen, CO2, steroids as well as water (through gaps)

vesicular transport

transport large macromolecules that are unable to pass through the membrane

intracellular fluid

fluid within cells

2/3 of total body water

interstitial fluid

fluid between cells

Fluid intake must equal fluid output

homeostasis

molecules with a greater extracellular concentration

Na, Ca, Cl, HCO3-, glucose

molecules with a greater intracellular concentration

K, Mg, P, amino acids, ATP, protein

what is K+ most crucial for in the cell?

maintaining membrane potential

What is Ca2+ most crucial for in the cell?

muscle contraction and process involved in neurotransmitter release from the transmissive segment of neuron

positive feedback

reinforces a stimulus to produce an even greater response, requires major event to restore homeostasis

negative feedback

opposite action to stimulus

hypotonic solution

Solute concentration is less than that inside the cell; fluid flows into the cell to even it out (lysis)

hypertonic solution

Solute concentration is greater than that inside the cell; cell releases water to even it out (crenation)

passive membrane transport

does not require the cell to expend energy

diffusion

Movement of solutes from an area of higher concentration to an area of lower concentration to reach equilibrium

Osmosis

net movement of water through selectively permeable membrane

Osmolarity

total concentration of all solute particles in a solution

osmolarity trend

higher osmolarity, the lower water concentration

isotonic solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

What affects the rate of diffusion?

- greater concentration gradient (faster)

-higher temperature (faster)

-larger size (slower)

-increase in surface area (faster)

-increased diffusion distance, (slower)

permeability coefficient

An estimate of the ease by which a molecule can pass through a cellular membrane; dependent especially on the lipid solubility of the molecule.

what is a major factor limiting diffusion across a membrane

hydrophobic interior of lipid bilayer

what molecules diffuse rapidly across the membrane

O2, CO2, fatty acids, steroid hormones

polar molecules are hydrophilic, so...

they do not readily diffuse and require a protein transporter

simple diffusion

involved no transport mechanism, small nonpolar molecules readily pass through the plasma membrane

facilitated diffusion

requires membrane protein transporter (ion channels or carrier proteins)

non gated leak channels

always open for ions and water

chemical/ligand gated channels

open and close in response to chemical stimulus like hormones, neurotransmitters, ions

mechanically gated channels

open with mechanical stimulation (least common)

voltage gated leak channels

open in response to change in voltage

initiation and propagation of action potential)

What do sodium channels mediate?

fast depolarization of action potential (rapid influx of Na+ inside a cell makes it less negative and more positive)

Sodium channel blockers

Slow the rate of impulse conduction through the heart, reduces cell excitability and conduction velocity

TTX (tetrodotoxin)

irreversibly binds on Na channel blocking ion influx into cell preventing depolarization

What do potassium channels mediate?

K+ outflow resulting in hyper-polarization during an action potential

Potassium channel blockers

blocks repolarization that would allow for initiation of another action potential

TEA (tetraethylammonium)

previously used to treat heart arrhythmia and HTN (K+ channel blocker)

potassium chloride

used in lethal execution procedure (K+ channel blocker)

active transport

uses ATP or an ion to drive substances against concentration gradient

primary active transport

direct use of ATP; Na+/K+ ATPase pump establishes and maintains membrane potential of a cell