normal cell: structure and function - lecture 1

cells are the fundamental units of life. a lot of communication between cells/tissues/systems

why are we interested in the structure and function of the normal cell?

cell

understanding pathophysiology begins with understanding the ...

disease (if not resolved or injury persists)

injury to any cellular component can lead to...

crohn's disease and skin carcinomas

epithelial cells are associated with ...

marfan syndrome and rheumatoid arthritis

connective tissue cells are associated with...

sarcopenia and heart failure

muscle cells are associated with ...

parkinson's and alzheimer's

neural cells are associated with...

epithelial cells

cover and line body surfaces, specialized for the selective secretion and absorption of ions and organic molecules and for protection, replicate (turnover) often to replace damaged or dead cells, aid in the transportation of filtered material through the use of active transport systems, innervated and provide sensory information, AVASCULAR

stomach lining, skin, etc.

what are some examples of epithelial cells

types of epithelial cells

epithelial cells

in diseases such as eczema, psoriasis, dermatitis, peptic ulcers, and barret's esophagus, what cells are the target?

connective tissue cells

connect, anchor, and support the structures of the body. MOST ABUNDANT CELLS IN THE BODY. form a framework of the body. the two major structural proteins are COLLAGEN AND ELASTIN.

connective tissue diseases

any disease that has the connective tissue of the body as a primary target of pathology

leukocytes (white blood cells)

many connective tissue diseases feature abnormal immune cell activity with inflammation called...

collagen

fibroblasts secrete ___________, which is important for maintaining the structural framework of tissues and extracellular matrix (ECM). plays a critical role in wound healing

connective tissue cells

in diseases such as rheumatoid arthritis, lupus, scleroderma, marfan syndrome, and ehlers-danlos syndrome, what cells are the target?

skeletal, cardiac, and smooth

what are the 3 types of muscle cells in the human body

skeletal muscle

anchored by tendons to bone and is used on skeletal movement such as locomotion and in maintaining posture. VOLUNTARY MUSCLE

cardiac muscle

similar skeletal muscle but only found in the heart. INVOLUNTARY MUSCLE

smooth muscle

found within the walls of organs and structures such as the esophagus, stomach, intestines, bladder, blood vessels. INVOLUNTARY MUSCLE

muscle cells

in diseases such as Lou Gehrig's disease, atrophy, muscular dystrophy, myasthenia gravis, and cardiomyopathy, what cells are the target cells?

involuntary muscle

A muscle that is not under conscious control.

voluntary muscle

A muscle that is under conscious control

neuron

a cell of the nervous system that is specialized to initiate, integrate, and conduct electrical signals to other cells

nerve cells/neurons

in diseases such as multiple sclerosis, parkinson's, alzheimer's, stroke, shingles, and depression, what cells are the target?

brain and spinal cord

what are the two parts of the central nervous system

autonomic (sympathetic and parasympathetic) and somatic (sensory afferent and motor efferent) nervous system

what are the two parts of the peripheral nervous system

semipermeable membranes

form a major structural element in cells

phospholipid bilayer

cell is surrounded by a ....

1. separate or compartmentalize ions and molecules (allow for the development of fluid compartments in body)

2. detecting chemical signals from other cells

3. link adjacent cells together by membrane junction

what are the 3 functions of cell membranes

fluid compartments

separated by selectively permeable membranes that control movement of water and solutes

60

____% of our body weight is water

intracellular fluid

fluid within cells

extracellular fluid

fluid outside the cell (interstitial fluid and plasma)

interstitial fluid

fluid between cells

the fluid will start going to the hypotonic compartment to balance the tonicity creating an isotonic environment

if you have two compartments and a selective permeable membrane in between them with hypertonic and hypotonic compartments (as pictured), what will happen?

cell membranes

act as barriers that considerably slow the diffusion of molecules across their surfaces

lipophilic (hydrophobic)

____________ compounds can pass through the cell membrane

hydrophilic

_____________ compounds do not pass through

hydrophilic compounds

specialized transporters and channels allow transport of ....

high, low

solutes want to move from area of ______ concentration to area of _____ concentration

proteins imbedded in the cell membrane

control diffusion across the membrane and set up concentration differences

simple diffusion

movement from high to low concentration

facilitated diffusion

movement from high to low concentration with the help of a transporter

active transport

movement against concentration gradient, with a transporter needing ATP

ECF volume

amount of sodium in body is a prime determinant of the ...

ECF

solutes (NaCl) are confined to the

increases

dietary salt (NaCl) overload and ____________ total solute in the ECF

decreases

dietary water overload ___________ total solute in the ECF

increase in plasma volume as a result of increased Na+

an excess of Na+ in the body isnt recognized by alterations in Na+ as you might think, but rather by the ...

osmosis

the movement of water across a semi permeable membrane

osmolarity

the total concentration of all solutes in a solution. defined as the number of osmoles of solute per liter of solution

penetrating solutes (nonpolar) and non penetrating solutes (polar)

osmolarity takes into account the total concentration of...

tonicity

the ability of an extracellular solution to make water move into or out of a cell by osmosis

osmolarity

a solution's tonicity is related to its ...

types of solutions

if you add 0.9% of a saline solution (isotonic solution) nothing will happen between the red blood cells and the environment. but if you have a hypotonic solution with low saline, water will come in the red blood cells because it is more concentrated. if you have a hypertonic solution with a higher saline concentration, the water will leave the cell and it will shrink

how can tonicity affect red blood cells

hypertonic solution

causing the cell to shrivel because the fluid will move out

isotonic solution

Equal solute concentration inside and outside cell.

hypotonic solution

a solution that causes a cell to swell because fluid will move into the cell

cells

regulate their responses to chemical messengers by increasing (upregulation) or decreasing (downregulation) the number of active receptors on their surface

signal transduction

depends on cell type and location, response can be channel opening, action potential generation, changes in gene expression, etc.

autocrine, gap junctions, paracrine, endocrine, neuroendocrine (responds to NS stimulation), hydrophilic, lipophilic signal

what are the different types of cell communication

autocrine

cell targets itself

signaling across gap junctions

cell targets a cell connected by gap junctions

paracrine

cell targets a nearby cell

endocrine

cell targets a distant cell through the blodstream

electrical potential

electro-chemical gradient, inside of cell is negative compared to outside

resting membrane potential

the electrical charge of a neuron when it is not active

graded potentials

hyperpolarize (IPSP), depolarization (EPSP)

action potentials

short periods of electrical activity at the membrane of a neuron, responsible for the transmission of signals within the neuron

neurons

communicate by chemical and electrical signals

depolarization

Loss of a state of polarity; loss or reduction of negative membrane potential

repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.