Physiology Exam 1

What are cells?

Smallest unit of life. 200 types. 4 major classes: nerve, epithelial, muscle, and connective

Neurons

Cells that transmit information as electrical signals. Have branches that receive and transmit signals to other cells

Muscle Cells

Muscle fibers. Contract which makes mechanical force and movement.

Skeletal Muscle

Voluntary control of limbs

Blood Vessel Muscle type

Smooth muscle

Epithelial cells

Sheetlike layer of cells in combination with a thin under layer of noncellular material called the basement membrane.

Where is epithelial tissue?

Found where body fluids must be kept seperate from the external environment. Also organ linings.

Lumen

Lines the inside of hollow organs.

Example of transportation done by epithelial cells in the stomach

cells in the lining of the stomach move acid (hydrogen atoms) into the lumen of the stomach to help digestion.

Example of epithelial cell transport in the intestines.

Cells move organic molecules from the lining of the intestine to the blood.

Exocrine Gland

secrete a product into a duct leading to an external environment

Endocrine gland

secrete hormones into the bloodstream

Hormones

Chemicals that communicate a message to cells of the body and into the bloodstream.

Tissue

Collection of cells that have the same function

Organ

When two or more tissues combine to carry out a function.

What tissues does the heart have?

mainly muscle tissue, nervous tissue (control the heartbeat), epithelial tissue (lines the hearts chambers), and connective tissue (which makes up the heart valves and other tissues that hold the muscle fibers together).

Organ System

Collections of organs that work together to preform a certain function. Organs can be physically connected or disconnected and widely scattered. Many organs function in more than one organ system.

Cardiovascular System

Organ system: Function is to deliver blood to all of the body’s tissues. Includes the heart, blood vessels, and the blood.

Gastrointestinal system

function is to break down food into smaller molecules and then transport those into the blood. Includes the mouth, salivary glands, esophagus, stomach, intestines, liver, gallbladder, and pancreas.

Endocrine System

Organs are scattered throughout. Encompasses all the glands in the body that secrete hormones. Function is to provide communication between cells of the body through the release of hormones into the blood. Hypothalamus, pituitary gland, adrenal gland, thyroid gland, parathyroid gland, thymus, and pancreas.

Immune system

Organs scattered throughout. Protects the body from invading microorganisms and other foreign materials.

What are all of the organ systems?

1. Endocrine

2. Nervous

3. Musculoskeletal

4. Cardiovascular

5. Respitory

6. Urinary

7. Gastrointestinal

8. Reproductive

9. immune

10. Integumentary

Nervous System

Function is to provide communication between cells of the body through electrical signals and the release of neurotransmitters into small gaps between certain cells. Includes the brain, spinal chord, and peripheral nerves

Musculoskeletal

Purpose is to support the body and allow voluntary movement of the body including facial expressions. Includes skeletal muscle, bones, tendons, ligaments.

Respiratory System

Function is to bring oxygen into the body and eliminate carbon dioxide from the body. Includes the lungs, pharynx, trachea, and bronchi.

Urinary

Function is to filter the blood to regulate acidity, blood volume, and ion concentration. Eliminates waste. Includes the kidneys, ureters, bladder, and urethra.

Reproductive System

Function is to generate offspring. Includes gonads, reproductive tracts and glands.

integumentary system

Protects the body from the external environment. Includes the skin.

What organ systems does the pancreas participate in?

Digestive system because it secrets fluid and digestive enzymes into the intestines. Endocrine system because it secretes certain hormones.

How does the External environment become internal

Most cells are not able to exchange directly because there is no contact. Cells receive oxygen and nutrients from the bloodstream which also caries waste away from the cells. Most cells are not in direct contact with the blood but are surrounded by fluid that exchanges materials.

Internal Environment

Immediate environment of most cells. Fluid that surrounds the cells.

Exchange from external to internal environments:

Inspiration: oxygen enter the bloodstream from the lungs

Expiration: carbon dioxide leaves the lungs.

Absorption: takes the nutrients from food and water.

Excretion: elimination by feces

Secretion: when the stomach needs stuff to break down food that is secretion.

Filtration: fluid enters tubules

Reabsorbtion: needed materials are selectively transported back into the blood

What is in urine?

Cellular waste products, excess salts, and water.

What is the most abundant fluid in the body?

Water. It acts as a solvent for a variety of solutes in the body fluids.

What are the solutes in the body?

small molecules: Inorganic ions, sugars, and amino acids

Large Molecules: proteins

What sperates the contents of the cells from there surroundings?

Epithelial tissue and cell membranes

Permeable

Describes cell membranes. Allow molecules to pass through. Some molecules pass easier than others.

What is total body water?

the total colume of fluid enclosed within the outer epithelial layer. for a person weighing 70kg it is 42L or about 60% of total body weight. Includes water present inside and outside of cells.

Intracellular fluid

Inside the cell. Contains many proteins and is rich in potassium

Seperated by cell membranes

What is the ratio of ICF and ECF in total body water

ICF - 2/3

ECF - 1/3

Extracellular fluid

Extra - outside the cell - internal environment. Contains few proteins and is rich in sodium. 20% of EFC is found in the blood and the rest is found outside the blood.

Why do ICF and ECF have different compositions?

The different compositions support the proper functioning of cells and are made possible by relatively low permeability of cell membranes.

Plasma

20% of ECF. Liquid and noncellular part of the blood.

Interstitial fluid

80% of ECF and it is found outside of the blood

What is the difference between plasma and interstitial fluid?

Interstitial fluid has little protein. plasma has a lot of protein.

Why are plasma and interstitial fluid almost the same?

the walls of the smallest and most numerous blood vessels (capillaries) are highly permeable to most solutes except protein.

How many organ systems maintain homeostasis

9/10

What can’t change to keep the internal environment regulated

Composition, temperature, and volume of extracellular fluid.

Regulated variable

not free to vary but is instead regulated to stay within relatively narrow limits

Negative Feedback

If a regulated variable increases, the system responds by making it decrease. If it decreases the system makes it increase.

Set Point

Normal “desired” value

Error signal

is caused by any difference between the actual value and the set point.

Sensors

Cells (often neurons) that are sensitive to the variable in question

Thermoreceptors

sensitive to temperature

Chemorecepters

Sensitive to oxygen and carbon dioxide in the blood.

Integrating center

sensors relay signals to it. A particular set of neural circuits in the brain or an endocrine gland. Compared the regulated variable to the set point and says what the appropriate response is. Relays output to the cells, tissues, or organs that bring the final response

Effectors

Listens to the integrating center to see the appropriate steps.

Positive Feedback

the response of the system goes in the same direction as the change that sets it in motion.

Diabetes Mellitus

Metabolic disease that affects blood glucose levels and plasma volume and causes excessive thirst and fluid loss. Affects every system in the human body. “to siphon” “honey sweet” blood and urine glucose levels elevated. Plasma volume effected.

Parietal

Connected to body walls

Visceral

Surrounding organs

Peritonea/Peritoneum

Tissue connecting and holding organs to each other

Mesentary

Tissue between organs; creates a membranous sac that holds peritoneal fluid.

Na+

always more concentrated outside of the cell in the extracellular fluid

K+

Always more concentrated inside the cell or in the intracellular fluid (cytosol)

General Feedback System

1. Parameter/variable

2. Sensors/receptors

3. control center

4. Effector/response

Afferent vs Efferent Nerves

Afferent takes info from outside and brings it to the spinal cord. Efferent takes signals from the spinal cord to the muscle to react.

Childbirth feedback loop

Baby’s head stratches cervix (stimulus; data sent to brain (control center); signals uterus (effector); uterus stimulates brain production of oxytocin; uterus produces prostaglandins that stimulate more oxytocin production; oxytocin stimultes more uterine contractions (response)

Contractions move babys head causing more cervical stretching and stimulates the release of more hormone - amplified

Pitocin

Synthetic oxytocin - induces labor; stimulates contractions; initiates feedback loop.

Type 1

Lack of insulin. 5-10% of all cases

Types 2

Impaired response to normal insulin levels

Pre-Diabetes

Blood glucose 00-125 mg/dL. 79 million americans. develope type 2 in 10 years

Gestational Diabetes

Subclass of type 2. Affects 4% of pregnant women. May develop type 2 post pregnancy.

Diabetes insipidus

Insipid urine. Unrelated to DM. affects antidiuretic hormone (vasopressin) - aquaporin 2 system.

Fasting Plasma Glucose Test

Normal: 60-100 mg/dL

Pre-diabetes: 100-125 mg/dL

Diabetes: >125mg/dL

Oral Glucose Tolerance Test

Normal: < or equal to 139 mg/dL

Pre-diabetes: 140-199mg/dL

Diabetes: > or equal to 200

Hemoglobin A1c

Estimates blood glucose for 2-3 months

Diabetes treatment

Maintaining blood glucose lower than 120 reduces eye disease, kidney disease, and nerve damage. Diet, insulin(for insulin resistant forms), sulfonylureas and meglitinides (stimulate pancreatic beta cells to secrete insulin), and Thiazolidinediones (enhance insulin effects and decrease liver glucose production).

Inorganic Compounds

Usually don’t contain carbon. come from the earth. Simple molecules. Ex: water

Organic Compounds

Always contain C and H. Usually O, N, and sometimes S and P. originate in organisms. Complex. Ex-protein

Chemical Reactions

The conversion, accumulation, and disposal of substances by a cell is done through energy-driven reactions. Chemical bonds are broken, formed, or rearranged or electrons are transferred between atoms.

Monomers

Single unit. micromolecule

Polymer

multiple units of monomers attached to each other. Macromolecule made up of repeating identical or similar subunits. DNA, RNA, Proteins, Carbs, Lipids.

Monomer —> Polymer

Amino Acids —> Protein

Fatty acids/glycerol —> Fats/lipids

Flucose/Fructose —> Carbohydrates

Sugar / Phosphate / N-Bases —> Nucleic Acids (DNA/RNA)

Biomolecules

Molecules synthesized by living things. Contains Carbon

Four Basic Biomolecule types

Carbohydrates, lipids, amino acids and proteins, nucleotides.

Carbohydrates

Polysaccharide - glycogen - Contains C, H, and O - Monomers - 1C:2H:10 - (CH2O)

Polymers: (CH2O)n = polysaccharide

Glycosidic bond between monomers

Glycogen (storage polymer of glucose) synthesized and stored in: liver(blood glucose), muscles, brain, uterus, and vagina.

Monosaccharide of Carbs

Glucose, Fructose, Galactose

Disaccharide Carbs

Maltose, sucrose, lactose

Polysaccharide Carbs

Starch, glycogen, cellulose

Glycoproteins and glycolipids

Formed by polysaccharides covalently bound to proteins or lipids

Lipids

Contains Carbon, Hydrogen, and Oxygen. Monomers - (1C:2H)n:2O = C15H31COOH (fatty acids)

Polymers - triglycerides (3 fatty acids + glycerol).

Lipids (hydrocarbon waxes and oils) include fatty acids, triglycerides, phospholipids, eicosanoids, and steroids.

Saturated Fatty acids

Solid at room temp. No double bonds between carbon atoms; carbons are saturated with maximum number of hydrogen atoms. Trans-fat

Phospholipids

Glycerol backbone, two fatty acid “tails” and one phosphate ‘head’ in place of third fatty acid. Vital to structure of the cell membrane.

Amphiphilic

Molecule with polar group (phosphate head) and nonpolar group (fatty acid tail)

Ketones

Hydrolysis of triglycerides in adipose tissue, free fatty acids released in blood, some free fatty acids converted to ketones by the liver, acetoacetic acid, acetone, alpha-hydroxybutyric acid, buildup = ketosis (ketoacidosis), acetone breath.

Steroids

Non-polar. share four ring hydrocarbon structure called the steroid nucleus

cholesterol

Steroid that forms basis for all other steroids.

fatty acid

energy molecules and building blocks from polymers