Pathophysiology Chapter 2: Cell and Tissue Characteristics

Acromegaly

Condition of hyperplasia caused by hormone stimulation of excessive growth. Manifested by abnormal growth of the hands and feet in people how have stopped growing (epiphyseal ossification occurs)

Cerebral Atrophy's Effect on Neurons

Frontal & Temporal lobes: cognitive impairment Hippocampus and cerebral cortex: Alzheimer's disease Basal Ganglia: Movement disorders Recovery is severely limited due to the inability of neurons to replicate.

Genes vs. Chromosomes

Genes: Individual units of inheritance located on chromosome. Chromosome: coiled structure of chromatin forms genetic code.

Resting Left Ventricular Outflow Obstruction

When systolic pressure gradient reaches 30 mm Hg. It is moderate when it reaches 50 mm Hg or severe when it reaches 75 mm Hg.

Responses to Stressors on Cells

adaptation or death; mechanisms promote cell adaptation result from signals that cause changes in gene function; changes can be in size, number or structure

Cells

basic units that make up tissues; sites where changes in structure and function lead to symptoms and diseases

Cellular Respiration

series of metabolic processes that transforms fuel molecules into energy (ATP) and waste products

Ligand

signaling molecule; when ligand binds to receptor, it begins process of communication known as signal transduction pathway

Binding Affinity

tightness or strength of binding

Syncope

fainting

Organs

fully differentiated body parts with specialized functions

Syndactyly

fusion or incomplete separation of digit soft tissue. This is an alteration in process of apoptosis.

Tissues

groups of different cell types that combine to form a specific function

Proliferation

increase in cell number

Hypertrophy

increase in cell size usually from trophic or growth signals

Hyperplasia

increase in number of cells caused by hormone signaling - High altitudes increase blood cells

Cause of Secondary Cardiac Hypertrophy

increased blood pressure resulting in increased workload on the ventricle

Primary Cardiac Hypertrophy Without Known Cause

inherited non-sex linked genetic autosomal-dominant trait

Protesomes

large, recognize abnormally folded or formed proteins; involved in proteolysis (breakdown of proteins)

Paracrine Signaling / Local Mediators

ligand receptor binding that results in signal transduction with a local effect

Hormones

ligands involved in endocrine signaling; process is slower and longer lasting than paracrine signaling

Bilayer arrangement

lipid layers align so non-polar tail portions are intertwined and polar heads line both outer and inner surface of the cell

Tail

lipid structure of the lipid bilayer (phospholipid); composed largely of cholesterol; non-polar/hydrophobic

Cervical Dysplasia - S&S

none

Common Causes of Cell Injury & Death

"T-I-P-S" Toxins (chemical, pathogenic) Infections Physical injury (mechanical, chemical, thermal) Serum deficit injury (nutrition, hydration, oxygenation)

Cardiac Hypertrophy

AKA Hypertrophic Cardiomyopathy Disease of cardiac muscle that results from excessive workload and functional demand Most common cause of sudden unexpected cardiac death in young individuals (< 30 yrs of age)

Metaplasia

Adaptations that these cell types undergo, changing from one type to another type of cell in response to environmental stressors. Metaplastic changes of the cervix are not pathologic, the squamous epithelial cell component of the transformation zone is vulnerable to stressors which may cause the cells injure or damage.

manifestations of acromegaly

Altered facial features Prominence of jaw, brow Enlargement of tongue and lips Pain & numbness in hands Deepening voice Snoring Skin changes Altered reproductive functioning Breast discharge Impotence

Which of the following is true about a cell's cytoplasm?

Answer: The cell contains organelles. The cell is where protein is synthesized. The cell transports substances within the cell. The cell serves as its own digestive system. Explanation: Embedded in cytoplasm are various organelles, which function as the organs of the cell. These organelles include the ribosomes, endoplasmic reticulum, Golgi complex, mitochondria, and lysosomes. Ribosomes serve as sites for protein synthesis in the cell, whereas the endoplasmic reticulum functions as a tubular communication system that transports substances from one part of the cell to another. Lysosomes are viewed as the digestive system of the cell. The nucleus is the site for the synthesis of the three types of ribonucleic acid (mRNA, rRNA, and tRNA) that move to the cytoplasm and carry out the actual synthesis of proteins.

A client with end-stage renal disease has been on peritoneal dialysis at home. Based on the lab work, the client regulates the type of solution to infuse into the abdomen. When there is a high concentration of potassium inside the cell (hyperkalemia), the solution infused has a lower concentration so that the potassium ions will diffuse outward. At this point, the cellular membrane is said to be:

Answer: polarized because of the presence of a negative membrane potential. Explanation: Because of the large concentration gradient existing across the cell membrane, potassium ions tend to diffuse outward. As they do so, they carry their positive charges with them, causing the inside to become negative in relation to the outside. This new potential difference repels further outward movement of the positively charged potassium ion. The membrane is said to be polarized.

Which type of epithelium is found in the lining of blood vessels, lymph nodes, and alveoli of the lungs?

Answerr: Simple squamous epithelium Simple squamous epitheliumi s adapted for filtration, which works well on the blood vessels, lymph nodes, and alveoli of the lungs. Stratified squamous keratinized epithelium makes up the epidermis of the skin. A pseudostratified ciliated columnar epithelium with goblet cells forms the lining of most of the upper respiratory tract. Transitional epithelium is well adapted for the lining of organs that are constantly changing their volume, such as the urinary bladder.

Causes of Injury to Epithelium

Chronic infection Irritation Trauma

Which body process uses cell differentiation?

Correct response: A bone marrow transplant is successful. Oral mucosa repairs ulcers post-chemotherapy. Explanation: Stem cells in the bone marrow are undifferentiated enough that they can completely rebuild the hematopoietic and immune systems from a transplant. The stem cells lining the gastrointestinal tract can also differentiate as needed. Skeletal muscle cells and nerve cells are highly specialized. Nerve cells do not have enough undifferentiated stem cells to regenerate while neither skeletal nor cardiac muscle can undergo the mitotic activity needed to replace/regenerate injured cells.

The nurse is assigned to care for the client with primary ciliary dyskinesia. What effect does this syndrome have on the body that the nurse should be aware of?

Correct response: Bronchiolitis Sinus aplasia A reversal of the thorax and abdominal organs Explanation: Primary ciliary dyskinesia (formerly Kartagener syndrome) is an example of immotile cilia syndrome and involves diffuse bronchiolitis, sinus aplasia, and situs inversus totalis, which is a reversal of the thorax and abdominal organs.

A client is having surgical removal of her gallbladder laparoscopically. While dissecting the gallbladder for removal, what type of epithelial tissue will be removed?

Correct response: Columnar Explanation: Columnar epithelial tissue is found on the lining of the intestine and gallbladder.

Tissues are composed primarily of cells in the M phase.

Correct response: False Explanation: Tissues may be composed primarily of quiescent cells in the G0 phase. The M phase is the phase during which cell mitosis occurs.

The Golgi complex, or Golgi bodies, consists of stacks of thin, flattened vesicles or sacs within the cell. These Golgi bodies are found near the nucleus and function in association with the endoplasmic reticulum (ER). What is one purpose of the Golgi complex?

Correct response: Receive proteins and other substances from the cell surface by a retrograde transport mechanism Explanation: Recent data suggest that the Golgi apparatus has yet another function: it can receive proteins and other substances from the cell surface by a retrograde transport mechanism. Golgi bodies do not produce bile. They produce secretory, not excretory, granules, and they produce large carbohydrate molecules rather than small ones.

The student is studying membrane potentials. Which membrane potential is essentially a potassium equilibrium potential?

Correct response: Resting membrane potential Explanation: The resting membrane potential, which is necessary for electrical excitability, is present when the cell is not transmitting impulses. Because the resting membrane is permeable to potassium, it is essentially a potassium equilibrium potential.

How does facilitated diffusion enable molecules to cross cell membranes?

Correct response: Transport proteins carry molecules to areas of lower concentration. Explanation: Diffusion is movement of a substance across cell membranes in the direction of a lower concentration. Facilitated diffusion also moves substances to areas of lower concentration, but with the assistance of a carrier molecule. Ion channels are proteins that allow certain electrolyte ions to pass rapidly through the membrane. Active transport occurs when a transport protein carries substances across the cell membrane toward an area of higher concentration.

The process responsible for generating and conducting membrane potentials is:

Correct response: diffusion of current-carrying ions. Explanation: Membrane potentials rely on the permeability of the cell membrane and the diffusion of electrically charged ions. If voltage-gated channels remain closed, membrane potential cannot be generated. Ion channel neurotransmitters are involved with opening protein channels for purposes of cell-to-cell communication.

A teenager has experienced repeated bacterial infections throughout her life and has recently been diagnosed with leukocyte adhesion deficiency. The nurse explains that this is caused by the teenager's inability to:

Correct response: synthesize appropriate integrin molecules. Explanation: Persons affected with leukocyte adhesion deficiency are unable to synthesize appropriate integrin molecules. As a result, they experience repeated bacterial infections because their white blood cells are not able to transmigrate through vessel walls.

When does the body make the most lactic acid?

Correct response: During cardiac arrest During intense exercise Explanation: Lactic acid is produced from pyruvate during anaerobic metabolism, which occurs during intense physical exercise, cardiac arrest, and circulatory shock. Gluconeogenesis is the process by which the liver converts lactic acid back to glucose. Fat metabolism produces fatty acids that are broken down into acetyl CoA, which enters the citric acid cycle.

Which statement regarding cell metabolism is most accurate?

Correct response: Glycolysis also provides energy in situations when delivery of oxygen to the cells is delayed. Explanation: Glycolysis provides energy in situations when delivery of oxygen to the cells is delayed or impaired. Anabolism is a constructive process, in which more complex molecules are formed from simpler ones. Energy from foodstuffs is used to convert ADP to ATP. The aerobic pathway occurs in the mitochondria.

A nurse practitioner (NP) has been asked to address the local high school basketball team regarding health and nutrition. One player asks how the pizza he ate last night is converted to energy that he can use today when he goes to practice. Which response is the best answer?

Correct response: Nutrients are converted to ATP, and when ATP undergoes hydrolysis, it transfers energy to molecules in the cells for their use. Explanation: Cellular metabolism (catabolism) of carbohydrates via glycolysis, TCA cycle, and the mitochondrial electron transport chain converts the caloric energy into the chemical energy of ATP. ATP is hydrolyzed by enzymes in the cell to liberate the stored energy.

Which type of tissue forms the architecture of liver sinusoids and lymphoid tissues such as the spleen?

Correct response: Reticular connective tissue Explanation: Reticular connective tissue is characterized by a network of fibers interspersed with fibroblasts and macrophages. Reticular tissue forms the architecture of liver sinusoids, adipose tissue, bone marrow, and lymphoid tissues such as the spleen.

A nurse practitioner (NP) has been asked to speak with the local high school track team about health, wellness, and nutrition. One of the athletes asks about the differences in the physiology of the energy used in sprinting versus long-distance running. Which response is the best answer?

Correct response: Sprinters utilize ATP generated via anaerobic glycolysis, and distance runners utilize ATP generated via aerobic metabolism. Explanation: The use of anaerobic glycolysis by sprinters is due to the rapid demand for ATP, which outpaces the ability to produce it. Distance runners utilize ATP as it is synthesized; therefore, they may run for much longer. Diet does not affect muscle function on a cellular level. A reference to "explosive" or "slow, steady" energy does not explain the physiology of the matter.

In which parts of the body are smooth muscles found?

Correct response: Stomach Renal ureters Blood vessels Explanation: There are three types of muscle tissue. Cardiac and skeletal muscles are striated and a located in the heart and muscles that support the body. Smooth muscle is not striated and is found in the iris of the eye, stomach, urinary bladder, and hollow tubes such as blood vessels, ureters, and the common bile duct.

Which statements describe epithelial tissue cells? Select all that apply.

Correct response: They have no blood vessels. They require moisture. They are classed by shape. Explanation: Epithelial cells are closely joined together, have an underlying basement membrane, are avascular, and must be kept moist to survive. They have three surfaces: a free (apical) surface, a lateral surface, and a basal surface. Epithelial cells are classified by the number of layers and the shape of the cells.

Which statement made by the student nurse demonstrates that teaching about the Krebs cycle has been effective?

Correct response: "It provides the final common pathway for the metabolism of nutrients." Explanation: The Krebs cycle provides the final common pathway for the metabolism of nutrients. Glycolysis is the process by which energy is liberated from glucose.

A client has been diagnosed with a genetic disorder that affects his voltage-gated sodium channels, increasing his risk of sudden cardiac death. In a healthy individual, what role do ion channels perform in the body?

Correct response: Allow for membrane potentials to be established in excitable cells for rapid ion movement Explanation: Membrane potentials occur at the level of the cell membrane; ion channels allow for the passage of charged particles in and out of the excitable cell. Membrane potentials do result from the binding of sodium and potassium ions, both of which have a positive charge. Gated channels open and close in response to specific stimuil. Blood cells do not participate directly in the establishment of membrane potential in general, or the role of ion channels in particular. Ion channels do not respond to lipophilic or hydrophilic substances.

The cell surface is surrounded by a cell coat (glycocalyx.). Select the most important function of the cell coat.

Correct response: Cell-to-cell recognition and adhesion Explanation: The cell coat participates in cell-to-cell recognition and adhesion, and it contains tissue transplant antigens. Ribosomes serve as sites for protein synthesis in the cell; the Golgi apparatus modifies materials synthesized in the ER. DNA provides the information necessary for the synthesis of the various proteins.

What is an accurate explanation of why a client with iron deficiency anemia experiences fatigue?

Correct response: Cytochromes in skeletal muscle are less effective at transporting oxygen. Explanation: Clients with iron deficiency anemia frequently have reduced blood hemoglobin levels, but they also have less effective cytochromes in the muscles. Normally, cytochromes have a stronger affinity for oxygen than heme molecules, so they attract the oxygen molecules to enter the muscle cells. When iron is reduced, there is less transport of oxygen into the cells by the cytochromes.

A client experiences compartment syndrome after a leg injury. Surgical intervention will focus on which type of connective tissue?

Correct response: Dense connective tissue Explanation: Dense connective tissue such as muscle fascia forms the fibrous sheath around many organs and bone. Compartment syndrome is when the fascia fills with blood or fluid compressing the vascular and nervous connections to the extremity. Surgical release of the fascia is essential to restoring function of the extremity.

When discussing the various functions of the cellular parts, the pathophysiology professor asks a group of students, "Where are the primary sites of protein synthesis located in a cell?" Which student response is correct?

Correct response: Endoplasmic reticulum Explanation: The endoplasmic reticulum (with its associated ribosomes) and Golgi apparatus represent the primary sites of protein synthesis in the cell.

The nurse is caring for a client with liver failure. What process of conversion does the nurse know will be impaired due to the inability of the liver to remove lactic acid from the bloodstream?

Correct response: Gluconeogenesis Explanation: The liver removes lactic acid from the bloodstream and converts it to glucose in a process called gluconeogenesis. This glucose is released into the bloodstream to be used again by the muscles or by the central nervous system.

At which part of the cell is the action by the vinca alkaloid drugs directed during cancer treatment?

Correct response: Microtubules in the cytoskeleton Explanation: Microtubules are responsible for mitosis. The vinca alkaloid agents inhibit mitosis by binding to microtubules, which prevents formation of the mitotic bundle.

The nurse is performing an assessment with a client who presents with blisters on the skin and mucous membranes. What primary disorder of desmosomes does the nurse suspect the client may be suffering from?

Correct response: Pemphigus Explanation: A primary disease of desmosomes is pemphigus, which is caused by a buildup of antibodies to desmosome proteins. Affected people have skin and mucuous membrane blistering.

A nurse on the oncology ward in the hospital is doing some background research to better understand the molecular basis of cancer. She comes to the understanding that transformed cancer cells are very similar to a normal type of cell, with the exception of regulation of division. Which cell type found in the normal state is most similar to a cancer cell?

Correct response: Stem cells Explanation: Cancer cells and stem cells have very similar characteristics. They both are immortal and undifferentiated, unlike epithelial, muscle, and neural tissue. The primary difference between stem cells and cancer cells is the rate and regulation of division. Cancer cells have lost the ability to regulate the cell cycle.

A client with long QT syndrome has the gene that increases potassium channels. How will this affect membrane potentials? It will cause:

Correct response: delayed return to resting potential. Explanation: Action potentials involve rapid changes when the sodium channels open allowing sodium to enter the cell, quickly followed by the sodium channels closing and the potassium channels opening so potassium exits the cell. An increase of potassium channels means this will happen quickly. In long QT syndrome, the heart takes longer than usual to recharge between beats, causing a delay in reaching the resting potential. Equilibrium potential is the balance between the electrical potential and the diffusion potential.

While reviewing the basic information related to hemodialysis, the professor explains that water molecules move through adjacent phospholipid molecules in the cell membrane by:

Correct response: osmosis. Explanation: Water molecules move through adjacent phospholipid molecules in the cell membrane by osmosis without actually dissolving in the region occupied by the fatty acid side of the chains. Osmosis is regulated by the concentration of nondiffusible particles on either side of the membrane, with water moving from the side with the lower concentration of particles to the side with the higher concentration.

The nurse is caring for a client receiving colchicine for treatment of gout. The nurse knows the drug is effective because it:

Correct response: stops microtubules from forming. Explanation: Colchicine works by interfering with formation of the mitotic spindles made from microtubules that are necessary for cell mitosis. It also prevents migration of neutrophils and lowers their response to urate crystals in the tissues. The axoneme is part of the cell that produces mobility for cilia and flagella. The proteasomes are cell mechanisms for regulating the protein quality.

Rx for Dysplastic Ectocervix Cell

Cryopsurgery Cone biopsy/conization (with scalpel) Large-loop electrosurgical excision (LEEP)

Rx for Acromegaly

Drug therapy Radiation therapy Surgical removal of adenoma Chronic effects can be halted if identified early before permanent cell injury occurs.

Cervical Dysplasia - Risk Factors

Early-onset sexual activity Multiple (more than 3 sexual partners) Exposure to human papilloma virus (HPV) Smoking

When exercising outside on an extremely warm day, the client can feel his heart pounding very rapidly. Thinking in terms of the ability of the aorta to stretch to accommodate more blood circulating during exercise and the warm environment, this is an example of the function of which fibrous protein?

Elastin Explanation: Three types of fibers are found in the extracellular space: collagen, elastin, and reticular fibers. Elastin acts like a rubber band; it can be stretched and then returns to its original form. Elastin fibers are abundant in structures subjected to frequent stretching, such as the aorta and some ligaments. Collagen is the most common protein in the body. It is a tough, nonliving, white fiber that serves as the structural framework for skin, ligaments, tendons, and many other structures. Reticular fibers are extremely thin fibers that create a flexible network in organs subjected to changes in form or volume, such as the spleen, liver, uterus, or intestinal muscle layer.

Hormone Process that causes Growth (gland & hormone)

Hypothalamus - GHRH Pituitary - GH Liver - Insulin-like growth factor 1 (1GF-1) Hypothalamus - Somatostatin AKA GHIH

Hormone Process that causes Growth (gland & stimulates)

Hypothalamus - pituitary to release GH; Pituitary - liver to produce insulin-like growth factor 1 (1GF-1); Liver - hypothalamus to produce somatostatin AKA GHIH; Hypothalamus --.

Hormone Process that causes Growth (gland & function)

Hypothalamus --; Pituitary - causes cell cycle control responses/proliferation of cells; Liver - promotes growth of bone, cartilage, soft tissue and organs; Hypothalamus - Suppresses GH

Some Causes of Injury to Cells

Infection Physical injury Mechanical injury Thermal injury Endogenous (toxins from within the body) Deficit injury (such as oxygen deprivation)

Squamocolumnar Junction

Location at which the two types of cells merge. This area is dynamic throughout a woman's repro life, migrating and changing location on the cervix in response to stimuli such as hormones and pH. The area where the cells types merge is called the transformation zone.

Dyplasia

Refers to the actual change in cell size, shape, uniformity, arrangement and structure. In response to a chronic persistent stressor and is likely to resolve when the stressor is removed.

Gigantism

Same condition as Acromegaly but it occurs in youngsters prior to the closure of epiphyseal growth plate.

Cells of the Cervix

Squamous epithelium (outer side of cervix & vagina) Columnar epithelium (lines the endocervical canal)

Cytoskeleton

Structure composed of tubule and filament structures that contribute to cell shape, movement, and intracellular transport. Contains: - Microtubules - Microfilaments

Passive Transport

Substances enter cell passively with little energy required. Diffusion (movement from higher to lower concentration) is an example of Passive Transport.

Compliance

ability of the ventricle to contract without rigidity

Functions common to all cell types

Transportation Ingestion Secretion Respiration Communication Reproduction

Channel Protein

allows transport of ions (atoms with electrical charge) across plasma membrane

Rx for Secondary Cardiac Hypertrophy

as soon as it manifests and before cells undergo permanent damage. Treatment is geared toward relaxation of the ventricle and relief of the outflow obstruction. Antihypertensive meds are used to lower resistance in left ventricle when hypertension is the cause.

Glycolipid

carbohydrate bound to lipid; makes up bilayer but in smaller numbers than phospholipids

Differentiation

changes in physical and function properties of cells, directs cells to develop into specific cell types

Metaplasia

changing of one cell type to another; adaptation can occur: for example, people with GERD have the cells of the esophagus change from squamous epithelium to glandular cell type. Also bronchial tube cells change to adapt in smokers.

Gated Channel

channel that opens in response to stimulation

Leak Channel

channel that opens without the need for stimulation

Aerobic Respiration

chemical reactions of oxidation and reduction between oxygen and nutrient products such as glucose

Cellular Damage - most common environmental cause

cigarette smoking

Cytoplasm

colloidal substance surrounding cell nucleus; composed of water, proteins, fats, electrolytes, glycogen, and pigments

Endoplasmic Reticulum

complex network of tubules, producing proteins & fats; important in regulation of ions within cell; subway-tubular transport system Rough ER: contains ribosomes; synthesize proteins, produces lysosomal enzymes Smooth ER: no ribosomes; synthesizes lipid, lipoproteins and steroid hormones regulation of Ca, detoxifies certain drugs & hormones

Bronchopulmonary Dysplasia

condition where stressors prompt cell alteration leading to chronic, irreversible tissue changes. Caused by infants who need mechanical ventilation with high concentrations of oxygen. Bronchial and alveolar tissue become thickened and reduce air into lungs

Cervical Dysplasia

considered a precancerous condition

Necrosis

death of cells related to injury

Why does atrophy occur?

decrease in functional demand (limb in cast); decrease in oxygen supply to cell (ischemia); nutrition deprivation; aging process; involution (removal of hormonal signals that stimulate growth)

Atrophy

decrease in size of a cell

Membrane Pore

membrane passage between extracellular and intracellular environments

Golgi Apparatus

membrane structure; substances from ER go to GA and are packaged to be transferred out; prepares substances produced by endoplasmic reticulum for secretion out of cell ER=factory GA=Packaging & shipping dept

Perioxisomes

membrane-enclosed sacs smaller than lysosomes; contain enzymes (oxidase) that neutralize oxygen free radicals; promote cell survival by neutralizing harmful substances potentially damaging to cell

Concentration Gradient

movement from higher concentration to lower

Secondary Active Transport

movement of a second substance depends on energy derived from active transport of primary substance

Facilitated Diffusion

movement of some substances across membrane that need help of transport proteins for passage

Countertransport or Antiport

movement of substances in opposite directions

Semi-permeable Membrane

permits transport of some substance but acts as a barrier to others

Lipid Bilayer composition

phospholipids (Phosphate PO4-); phosphate connected to the lipid is the head

Apoptosis

physiologic and pathologic cell response to cellular signals. (A programmed cell death prompted by a genetic signals an is designed to replace old cells with new. AKA Cellular suicide. Could be due to damaged genetic material/mutation Old age of the cell

Usual Cause of Over-secretion of GH in Adults

pituitary tumor called an adenoma.

Purpose of the bilayer

prevents unintentional passage of water-based substances by hydrophobic cell surface

Anaerobic Respiration

process of ATP production that occurs without oxygen

Glycolysis

process of breaking down glucose in cytosol of cells; occurs in absence of oxygen, releasing only small amount of energy

Primary Active Transport

process requiring direct use of energy (ATP)

Endocytosis

process used to transport large substances into cells; Two types: Pinocytosis - ATP requiring process of ingesting small vesicles; Phagocytosis - process of ingesting large particles such as cells, bacteria, damaged cell components

Mitochondria

produces cellular energy source (ATP); contains cytochrome enzymes of terminal electron transport necessary for production of ATP; contains enzymes needed for the citric acid cycle, fatty acid oxidation, and oxidative phosphorylation

Transmembrane Proteins

proteins that pass through the membrane which allow communication and transport between extracellular and intracellular environments

Cerebral Atrophy

reduction in size of the cells in the cerebrum of the brain; progression leads to reduction in brain tissue

Feedback Mechanism

regulates gene activation to tightly control production of proteins and prevent cell damage caused by overproduction or underproduction

Active Transport

requires energy when transporting particles across membrane such as sodium potassium pump

Lysosomes

small sacs surround by membrane; digest cellular debris with hydrolytic enzymes; important in metabolism of particular substances

Integral Proteins

specific type of transmembrane protein that has tight binding to lipid tail and becomes part of membrane itself

Ligand-gated Channel

stimulated by receptor-ligand binding

Mechanically-gated Channel

stimulated by vibration, stretching, and pressure

Plasma Membrane

structure that protects the cell by creating barrier that separates intracellular components from extracellular environment surrounding it; comprised of lipids, carbohydrates, & proteins arranged in a bilayer

Organelles

structures within a cell that perform a distinct function

Colloid

substance microscopically dispersed evenly throughout another substance

Contransport or Symport

systems in which substances are transported in same direction

Reactive Oxygen Species (ROS)

toxic oxygen molecules or radicals that are formed by the reaction between oxygen and water during mitochondrial repiration.. Cell damage results from too many ROS or not enough available enzymes. ROS damages DNA Contributes to many diseases such as heart disease, diabetes, cancer ROS AKA Free Radical Injury

Bilayer

two interconnected layers

Exocytosis

vesicles move from Golgi into cytoplasm and then out of cell via cell membrane

Endocrine Signaling

wider range of impact occurs when signal transduction affects cell behavior within entire organism