Human Physiology

1st Step of Scientific Method

Make observations

2nd step of Scientific Method

Form a hypothesis, the hypothesis must be testable

3rd step in scientific method

Design a conductible experiment

Homeostasis

Dynamic Constancy in body’s Internal Environment

External Environment

The space that surrounds the body

Internal Environment

The extracellular fluid surrounds the cells of the body

What is Homeostasis controls

Body Temperature

Blood Volume

Blood Sugar

How is Homeostasis Maintained in the Body (Feedback System)

Controlled Variables

• Receptor

• Control Center

• Effector

Negative Feedback System

Blood Loss → Baroreceptor → Brain → Increased HR, Contractility, and cardiac output; Vasoconstriction

• Sympathetic Nervous System Activated

Endocrine Regulation of Homeostasis

Decreased Blood Sugar → (Consume sugars) → Increased Blood Sugar → Pancreatic Cells → Elevated Insulin Protection → Repeat

Positive Feedback System

• Strengthens or reinforces a change in a controlled variable

• Can only be stopped by some events outside the system

• Not Common

• Negative feedback regulates homeostatic conditions over long periods

4th step of Scientific Method

Analyze the data

5th Step of Scientific Method

Duplicate results to accept conclusion

6th Step of the Scientific Method

Several verified Hypotheses become a theory

Good Physiological Research requires

1.) Quantifiable measurements

2.) An Experimental and Control group

3.) Statistical Analysis

4.) Review and publication by peer-reviewed Journal

1st Step of Developing Pharmaceuticals

Basic research is conducted for years before drug given to person

2nd Step of Developing Pharmaceuticals

Research begins by studying the effects of a chemical on cells in vitro (in culture dish)

3rd Step of Developing Pharmaceuticals

Next, studies are done in animals (usually rats and mice) to see if the same effect occurs in vivid and if there’s any toxic side effects.

Phase 1 Clinical Trials

Test drug on healthy human volunteers to test for side effects, rates of passage and dosage

Phase II Clinical Trials

Tests Effectiveness on people with a particular disease

Phase III Clincal Trials

Conducted on large # of people, different races, sexes, and complex health conditions. Many drugs fail here

Phase IV Clinical Trials

Tests other applications of the drugs

1st Level of Organization

Molecule - Microscopic Level

2nd Level of Organization

Cell- Basic unit of structure and function of living things

3rd Level of Organization

Tissue- Group of similar cells that perform a similar function

4th Level of Organization

Organ - Group of two or more tissues into structure and functional units

5th Level of Organization

System- Group of organs that work together to perform related functions

6th Level of Organization

Organism- Systems working together in coordination

4 Major Primary Tissues

Muscle Tissue

Nervous Tissue

Epithelial Tissue

Connective Tissue

Muscle Tissue

Specialized for Contraction

Three Types

• Skeletal Muscle (Voluntary Muscles)

• Cardiac Muscle (Involuntary Muscles)

• Smooth Muscle (Hollow Organs; Bladder, blood vessels, bronchioles)

Nerve Tissue

Found In Brain, spinal cord, and nerves

Composed of Nerves and neuroglia

Function in communication

Epithelial Tissue

Forms Membrane that cover surfaces, line inside of hollow organs

Epithelial membranes are classified by # of layers

• Simple; one layer and for transport

• Stratified; multiple layers, provides protection

Connective Tissue

Characterized by a matrix made up of; protein fibers, extracellular materials, and specialized cells

Function of connecting and supporting

4 Major categories:

• Connective Tissue proper

• Cartilage

• Bone

• Blood

Organ Systems

Integumentary

Organs

• Skin, Hair, Nails

Primary Functions

• Protection, Thermoregulation

Organ Systems

Nervous

Organs:

• Brain, Spinal Cord, Nerves

Primary Functions:

• Regulation of other body systems

Organ Systems

Endocrine

Organs:

• Hormone-secreting glands, pituitary, thyroid, and adrenal glands

Functions

• Secretion of regulatory molecules called hormones

Organ Systems

Skeletal

Organs:

• Bones, Cartilages

Functions:

• Movements and support

Organ Systems

Muscular

Organs:

• Skeletal Muscles

Functions:

• Movements of the skeleton

Organ Systems

Circulatory

Organs:

• Heart, Blood Vessels, Lymphatic vessels

Functions:

• Movement of blood and lymph

Organ System

Immune

Organs:

• Red Bone Marrow, Lymphoid Organs

Functions

• Defense of the body against invading pathogens

Organs Systems

Respiratory

Organs:

• Lungs, Airway

Functions:

• Gas Exchange

Organ Systems

Urinary

Organs:

• Kidneys, Ureters, Urethra

Functions

• Regulation of blood volume and composition

Organ Systems

Alimentary

Organs:

• Mouth, Stomach, Intestine, Liver, Gallbladder, Pancreas

Function:

• Breakdown of food into molecules that enter the body

Organ Systems

Reproductive

Organs:

• Gonads, External genitalia, Associated glands and ducts

Functions:

• Continuation of the Human Species

Principle parts of cells

Plasma Membrane

Flexible, separates from the external environment of the cell, selectively permeable, communication.

Principal parts of cells

Cytoplasm

Fluid part of the cells (Cytosol) and little organelles that do the functions

Principal parts of cells

Nucleus

Contains DNA and directs cell activities

What passes through Plasma Membrane

Small, hydrophobic substances, such as Oxygen, CO2 and small lipid soluble molecules

Functions of Membrane Proteins

Ion Channels (integral)

Forms a pore, which specific ion can flow to cross membrane, include specific channels for specific ions

Functions of Membrane Proteins

Carrier (Integral)

Transports a specific substance across membrane by undergoing a change in shape. Example amino acids needed to, synthesis new proteins enter via ____ Proteins. Also known as ______

Functions of Membrane Proteins

Receptor (Integral)

Recognizes specific ligands and alters cell function in some ways. Example antidiuretic hormone binds to ______ in the kidneys and changes the water permeability of certain plasma membranes

Functions of Membrane Proteins

Enzyme (Integral and Peripheral)

Catalysts reactions occur both ______ and _____, the cell. Example Lactase protruding from epithelial cells lining small intestine splits the disaccharide lactose in the milk you drink

Functions of Membrane Proteins

Linker (Integral and Peripheral)

Anchors filaments ____ and _____ the plasma membrane giving shape and structural stability. May also link 2 cells together

Functions of Membrane Proteins

Cell Identity Marker (Glycoprotein)

Distinguishes cells, from anyone else’s. Important class of markers are major hisocompatibility proteins.

Other Plasma Membrane Components

Carbohydrates

Attached to lipids (glycolipids) and to proteins (glycoproteins); serve as antigens and interactions with regulatory molecules

Other Plasma Membrane structures

Cholesterol

Gives flexibility to membrane

Phagocytosis

• Large extracellular substances into the cell

• Some cells, like neutrophils and macrophages , can perform amoebiod movement by extending psuedopods to pull the cell forward.

• Pseudopods engulf bacteria, dead cells, r other organic materials and then fuse together to form a food vauole

• The food vacuole fuses with a lysosome, and the material is digested

  • Very important for body defense, inflammation, and apoptosis

Endocytosis

• Process for bringing large materials into the cells

• Plasma membrane furrows inward rather than extending outward. A Small part of the membrane surrounding the substance pinches off and is brought in as a vesicle

Encdocytosis (Pinocytosis)

Nonspecific

Endocystosis (Receptor-mediated endocytosis)

Specific, has receptor proteins in the membrane that will bind to the substance to be brought in

Exocytosis

• Large cellular products (proteins) are moved out of the cell

• The golgi apparatus packages proteins into vesicles that fuse to the plasma membrane, and the contents spill out of the cell

  • Used to release digestive enzymes, hormones, and neurotransmitters from certain cells

Cytoplasm

Materials in a cell

• Includes organelles, a fluid called cytosol, the cytoskeleton, inclusions

• Inclusions- Stored chemical aggregates such as glycogen granules, melanin granules, and triglycerides.

Network of protein filaments that extend through cytosol

• Provides structural framework

• Aids in movement

Three Types

• Microfilaments

• Intermediate filaments

• Microtubules

Microfilaments (Actin Filaments)

• Thinnest elements, made up of actin

• Most prevalent at the edge of the cell

• Functions

  • Help generate movements

  • Provide mechanical Support

    • Form microvilli

Microvilli

• Folds in the plasma membrane that increase the surface area for chemical reacations and rapid diffusion

• (Intestines)

Intermediate Filaments

• Intermediate in size

  • Smaller than microtubules. Larger than microfilaments

• Functions

  • Found in places where cells encounter stress

  • Help position organelles

  • Attach cells to one another

Microtubules

Largest of the cytoskeletal components

Hollow tubes composed mainly of tubulin

Functions

• Determine cell shape

• Movements of organelles

  • Found in cilia and flagella

Cilia

Tiny hairlike Structures composed of microtubules that project from the plasma membrane

Primary Cilium

Most cells have this nonmotile with “9+0” structure; may have a sensory functions in some cells

Motile Cilia

Propel fluid across surface of cells

1. Found in respiratory tract and uterine tubes

2. Has a “9+2” arrangement

Flagellum

1. A single whip-like structure that can propel a cell forward

2. Composed of microtubules with a “9+2” arrangement— similar to cilia but typically much longer

3. The sperm is the only cell in the human body with it

Organelles

1. Tiny specialized structures within the cell that have characteristic shapes

2. Perform specific functions in cellular growth, maintenance and reproduction

3. types

• Ribosomes

• ER

• Golgi

• Mitochondria

• Lysosomes, peroxisomes, and proteasomes

Mitochondria

1. Site of energy production (ATP)

• Structure

  • Inner membrane and an external membrane seperated by a intermemcrabous space

  • Inner membrane is folded into cristae to increase surface area for reactions

  • Central area is fluid and called the matrix

Ribosomes - Protein factory

1. Messanger RNA takes genetic information to the ribosome so a protein can be assembled

2. Very small; made of 2 subunits

3. Found free in the cytoplasm or associated with the granular endoplasmic reticulum

4. Serves as enzymes called ribozymes that are needed for protein synthesis

Endoplasmic Reticulum (ER)

1. The is a system of membranous passageways from the nuclear membrane to the plasma membrane

2. Granular (rough )

• Has ribosomes embedded on the outer surface

• Functions in protein synthesis and secreation

3. Agranular (Smooth ) has many functions, depending on the cell. Fatty acid and steroid synthesis

Golgi Complex (apparatus)

1. Transport vesicles made in the rough ER

2. Transport vesicles move to ____ _____

3. Proteins enter lumen of ____

4. Proteins modified as they travel through cristernae

5. Modified proteins are packaged and sorted

6. Secretory/new transport vesicles are formed, bring the proteins to the final destination

Lysosomes - Digestive Enzymes

• Membrane-enclosed vesicles containing digestive enzyme that digest a wide variety of substrates

Peroxisomes

• Smaller than lysosomes

• Contain oxidases that help metabolize amino acids and fatty acids

Proteasomes

Degrades unwanted or damaged proteins that are in the cytosol

Cell Nucleus

• Most cells have one ___

  • Muscle cells have hundreds; mature RBC have none

• The ___ is enclosed by the nuclear envelope made of two membranes

  • Outer membrane continuous with rough ER

  • Inner membrane often fused to outer by nuclear pore complexes, which allow small molecules and RNA to move in and out

• Cluster of DNA,RNA and proteins

• Gene expression

  • Genetic Transcription- The gene on the DNA is transcribed as messenger RNA, which can leave the nucleus

  • Genetic translation- The messenger RNA is then translated at the ribosomes to assemble the proper amino acid sequence

Genome

• Is all the genes in a particular individual or all the genes of a particular species

Proteome

All the proteins that are produced from the genome

How can a gene code fore more than one protein

• Posttransalational modification by

1. Methylation

2. Phosphorylation

3. Cutting into small units

Extracellular Environment

1. Includes everything located outside the cells

2. Cells receive nourishment from and release wastes into the ______ ______

3. Cells communicate with each other by secreting chemical regulators into the _____ _______

Body Fluids

1. 67% of our water is within cells in the intracellular compartments

2. 33% is in the extracellular compartment. Of this:

a. 20% is in blood plasma

b. 80% makes up what is called tissue fluid, or interstitial fluid; connects the intracellular compartment with the blood plasma

Transport of Bulk Molecules

1. Take in

Phagocytosis

Endocytosis (pintocytosis, receptor-mediated)

2. Spit out

Exocytosis

Plasma membrane permeability

Is selectively permeable

Passive Transport

Molecules move from higher to lower concentration without using metabolic energy

Active Transport

Molecules move from lower to higher concentration using ATP and specific carrier pumps

Noncarrier-mediated (passive)

1. Simple diffusion of lipid-soluble molecules

2. Simple diffusion of ions through channels

3. Simple diffusion of water = Osmosis

Carrier-mediated

1. Facilitated diffusion (Passive)

2. Active Transport (Active)

Diffusion Rate

Measured by the # of diffusing particles per unit of time

1. Steepness of concentration gradients — Driving force

2. Permeability of the membrane

3. Temperature of the solution

4. Surface area of the membrane — microvilli

Simple diffusion

1. Nonpolar molecules (oxygen, Carbon Dioxide, Steroid)

2. Ions and water molecules through specific channels

• Facilitated Diffusion: Carrier proteins

What can pass through the plasma membrane

Charged Ions can pass through an ion channel, that maybe gated. K⁺,Na⁺,Ca⁺²,Cl^-

Osmotic Pressure

Osmotic pressure is the force surrounding a cell required to stop Osmosis

A higher solute concentration would require a higher osmotic pressure

Osmolarity

• Unit of concentration that gives the total molarity of all soutes

• 2M glucose solution = 1M glucose + 1M fructose

• Water always goes from lower to higher

Normal Blood Plasma Osmolarity

300mOsM

Isotonic

Same osmolarity in the 2 environments (No net movement)

Hypotonic

Lower than plasma osmolarity, Will push water into the cell; cell will swell and could lyse

Hypertonic

Higher than plasma osmolarity; Will pull water out of the cell, cell will shrivel up and could crenate

Facilitated Diffusion —

Transport carriers for glucose are designated GLUT followed by the number of the isoform

GLUT 1

GLUT 2

GLUT 3

GLUT 4