Step 5: the process gets repeated many times. Each time, the DNA is doubled.

done by blocking transcription (or translation) via proteins called repressors

Hermaphrodites (animals that have both male and female reproductive systems)

1. mRNA attaches to a ribosome & a start codon must be read (AUG)
   

2. The next tRNA molecule moves in & matches with the mRNA codon
   

• Amino Acids form a peptide bond

3. The 1st tRNA can detach & mRNA moves over for the next tRNA to come in

5. The protein is formed and ready to finish folding to become functional

Neurotransmitters (charges in an ion concentration / chemicals released from nerve cells)

Types of Neurons

1. Sensory Neurons (carry info to CNS)
2. Motor Neurons (carry info away from CNS)
3. Interneurons (located between sensory and motor)
   
   

The General Senses

pain, touch, temperature (skin -- nerve endings can moderate their response based on the intensity of the stimulus) [touching snow or a hot stove]

body position (proprioception) muscle -- special neurons sense joint position, tension and muscle contraction [my leg popping out of place]

The Senses

Smell (receptor in the nasal cavity)

Taste (taste buds: sweet, salty, sour, bitter, urnami)

Vision (Retina -- receptors in the retina allow sight and mediate responses to changes in amounts of light)

Hearing/Equilibrium (receptors in inner ear -- determine the position in the body in space and interpret sound waves)

Sensory information is passed to your brain through the spinal cord

Spine protects spinal cord with bones called vertebrae
*Also known as a reflex center

Reflexes are automatic responses to a stimulus
*they're prewired in a circuit of neurons called reflex arc (sensory neurons that receive info from a sensory receptor, and interneuron that passes the information along and a motor neuron that sends a message to the muscle that needs to respond).

Cerebrum fills the whole upper part of the brain
Parts of the cerebrum:

Parietal Lobe processes information about touch and is involved in self-awareness

Frontal Lobe voluntary muscle movements, planning, memory, impulse control

Temporal Lobe processing sound and smell; good for memory and emotion

Occipital Lobe processes visual information

Cerebral Cortex wrinkly part; outer surface of cerebrum
conscious activity and higher thoughts

Corpus Callosum links the hemispheres; allows communication between the different sides of the brain

Thalamus main relay between spinal cord and cerebrum; first one to receive messages signaling pain, pressure, temperature.

Hypothalmus control center for many sensations (special senses: pleasure, sex drive, hunger, thirst)

Cerebellum controls balance, muscle movement and coordination

Brain Stem controls reflexes and spontaneous functions

Midbrain adjusts sensitivity of the eyes and ears

Pons relay messages between spinal cord and brain

Medulla Oblongata controls heart rate and sends info to spinal cord and brain

Dendrites (collect electrical signals)

Cell Body contains a nucleus and organelles

Axon delivers electrical signals to dendrites of another cell or to an effector cell

Terminal Boutons

Action Potential

Pharynx
Epiglottis (stops food from going into the lungs)

Esophagus brings food into the stomach, peristalis (muscle contraction which moves food down)

Mouth (mechanical digestion, chemical digestion through salivary glands i.e. sugars broken down), bolus created (ball of food)

Stomach bolus is turned into chyme

gastrin hormone produced by stomach

• stimulates upper part of stomach
• produces acidic gastric juices
• facilitates digestion
• triggers production of secretin and CKK
  (which causes pancreas and gallbladder to increase output of digestive juices)

Small Intestine chemical digestion, absorption of nutrients, chyme exposed to bile (liver synthesizes it)

• substances absorbed through "villi"
• blood and lymphatic vessel
  
  

Microvilli

• smaller villi
• increases surface area
• transports nutrients into blood vessels inside each villus

Gallbladder stores and concentrates bile
released into the small intestine to help dissolve fats

Stomach small % of alcohol is metabolized here.

Eating

• presence of food in stomach causes pyloric sphincter to stay closed
• stomach does not absorb alcohol as readily as the small intestine so it prevents alcohol from reaching the small intestine thus slowing the rate at which the alcohol reaches the blood stream
  
  

Alcohol Dehydrogenases

• enzyme secreted by epithelial cells lining the stomach
• help metabolize alcohol
  
  

*special variant of Al. Dehyd. "Acetaldehyde"

• differs by 1 amino acid
• popular in East Asian descent
• causes a more slowly metabolization of alcohol breakdown
• causes an increase in dizziness, flushed face, irregular heartbeat, nausea
  
  

If chyme has a high alcohol level

• stomach lining becomes irritated
• vomiting relfex

Small Intestine - majority of alcohol is broken down here - moved here by pyloric sphincter

• alcohol relaxes muscles involved with peristalis
• therefore, food spends more time in the digestive tract
• therefore, increased exposure to digestive enzymes

• therefore, diarrhea

  
  

• alcohol can interfere with the absorption of nutrients by damaging intestinal villi

Liver heavy drinking - leads to healthy liver tissue being replaced by scar tissue

• condition called cirrhosis

  
  

  progressive, irrversible process

  
  

• scar tissue prevents proper blood flow through the liver and can result in liver failure

Pancreas inflammation caused by excessive alcohol consumption

• pancreatitis prevents pancreas from secreting digestive enzymes
• thus disrupts digestion which can lead to life-threatening complications

Alcohol leaves the intestine and goes into the bloodstream.

• process to remove it from the body begins

• important to prevent damage i.e. decrease level of testosterone production thus, erectile dysfunction and lower sperm production

  
  

• removed by urinary system

unabsorbed materials pass through the large intestine (colon) and into the rectum and anus

removes waste & retains valuable materials for reuse and recycle

Kidneys filter & cleanses circulating blood

• sit behind the liver and stomach

• densely packed with looped tubules nephrons (1,250,000/kidney)

  
  

• capillaries surround nephrons

• lets waste diffuse out of blood & into tubules for excretion
• all blood is filtered 100s of times/day
  
  

Renal Arteries bring blood to kidneys

Sends waste through the ureters, bladder and stores urine in the urinary bladder then expelled via urethra

Waste Processing

1. Filtration occurs with in Bowman's capsule

• at the head of the nephron
• encloses the glomerulus
• Blood pressure forces plasma into nephron through tiny holes in the adjacent capillaries
  

2. Reabsoption

• sugars, amino acids and water are reabsorbed into the kidney tissue across the nephron loop
• salt actively removed from the filtrate on the ascending limb of the nephron loop becomes concentrated in the interior of the kidney causing water to flow out
  

3. Secretion

• waste low in concentration in the blood is actively secreted into the far end of the nephron.
• waste then flows into the collecting duct
  

4. Excretion

• After the filtrate is further concentrated as the collecting duct extends into the salty tissue of the kidney, urine is excreted into the bladder.

Micturition

• Alcohol promotes formation of urine, increases volume released by the bladder

Functions of the Urinary System
-regulates blood volume, acidity and salt balance

• waste management

*When BP is low, ADH is released by the petuitary gland which increases permeability of the collecting duct to water; thus lets increased amount of water from the filtrate return into the blood stream.

*When BP is high, ADH release is curtailed and more water is excreted

Anthrox

• lives in soil
• exists as a spore
  
  • lethal if inhaled
  • infections *not contagious
    
    

Botulism

• nervous system
• paralysis of facial and respiratory muscles
• botox (injections of the toxin produced by this bacterium)
• canned foods
  
  

E. Coili

• bacteria lives in the intestines of humans
• uncooked meat, bad milk
  
  

Staph

• bacteria on human skin and mucous membrane
• invades and destroys tissue

Vaccines - needed for school

DPT

• diptheria (respiratory)
  
  • pertussis (respiratory)
  • Tatnus (nervous/muscuar)
    
    

Bacterial Meningitus

• inflammation of membranes surrounding the brain
• death (10%) & disability
• spread through sneezes & coughs
• givevn to teens (spread through res)

• packs of DNA or RNA w/ protein coat (capsid)
• not living
• can't replicate w/o help of a host cell
• not made of cells - no enzymes for metabolism
• no ribosomes (can't make its own proteins)
• no cytoplasm or membrane-bound organelles (can't produce toxins like bacteria can)
• genome (genetic material) is DNA or RNA, circular or linear, circular or single stranded
• genes code for production of proteins needed to make more viruses inside of a host cell

• RNA viruses called "retroviruses" (packed with enzyme reverse transcriptase-- synthesize DNA from RNA)

  
  

• Animals

• extra structure outside capsid called "viral envelope"
• viruses surrounded by envelope called "enveloped viruses"

Viral Infection
animals - enveloped virus

• virus fuses its envelope with host cell's membrane *access granted
• humans unenveloped virus
• capsid proteins used to bind to receptor proteins in the plasma membrane of the host cell
• *viral genome enters cells
• once inside the host cell, capsid is removed
  

1. Enter (genome --> host cell)
2. Replicate (copied)
3. Exit (new virus leaves & leaves behind some viral proteins in host's cell membrane)
4. Spread (new viruses move to other cells and spread and infect)
   
   

Latent Virus

• dormancy i.e. herpes
• present but no symptoms for a while
  
  

Vaccines against Virus

• hepititus B (sexually transmited)
• babies vaccinated

• attacks the liver

  
  

• polio

• kids vaccinated, paralysis, death

  
  

• MMR (mumps, measles and rumbella)

  
  

• Chicken Pox

• causes brain swelling (encephalitis) & pneumonia
• older kids are affected
  
  

Gardasil

• college students
• protects HPV (causes reproductive cancer)
  
  

Flu Shot

Vaccines reduce the total number of susceptible individuals so disease doesn't spread as easily

Diseases Caused by Viruses

AIDS

• HIV is transmitted only through direct contact with bodily fluids
• [blood, semen, vaginal fluid]
• not tears, sweat or coughing, contact with clothes, phone or toilet seat
• Spread through needle sharing, unprotected sex, oral sex with infected partner
  
  

Common Cold

• 200 viruses cause colds
• rhinovirus most common cause
• Spread through droplets from sneezes or coughs or on objects i.e. utensils, doorknobs
  
  

Ebola

• Infected through wild animals or exposure to secretion of animals
• Spread through bodily fluids (even if dead)
• Exposure to medical supplies used to treat infected person
  
  

Mononucleosis

• affects young adults
• Symptoms: fever, fatigue, weakness, sore throat (1-2 months)
• transmitted in saliva when kissing, coughing or sneezing or touching contaminated objects
  
  

Rabies

• viral disease
• Spread through bite from infected animal
• Flu symptoms to paralysis, convulsions, hallucinations.
• Pets get the vaccine
• Spread through wild animals
  
  

West Nile

• transmitted to humans through bite of mosquito
• brain and spinal cord can become inflamed
• results in paralysis and death

Eukaryotic Pathogens

• single-cell protozoans & worms & fungi
• Spread by water and food contaminated with animal poop
  
  

Worms

• Worms gain access to body because of poor sanitation or eating contaminated meat / fish
• Worms live in the intestines or other organs
• Cause damage to internal tissues
  
  

Fungi

• cause diseases of the skin and internal organs
• damage tissue by secreting disgestive enzymes into it and absorbing products of digestion
  
  
  

Eukaryotic Pathogen Diseases
Giardiasis

• waterborne
• cyst
• enters water and food supplies in contaminated feces
• completes life cycle in intestines of infected person
• causes severe diarrhea and gas
  
  

Malaria

• caused by protozoans transmitted through mosquito bites in humans
• kills 2 million people / year
  
  

Schistosomiasis

• fresh water snails carry it
• caused by flatworms
• spread through contaminated water
• found in Asia, Africa, South America
  
  

Tapeworm

• caused by eating raw pork or beef
• worm lives in intestine
• causes abdominal pain and diarrhea
  
  

Athlete's foot & Jock Itch

• affect skin between toes, genitals, inner thighs
• Spreads easily through public places (locker rooms, pools, communal showers)
• Sweat can wash away naturally occuring fungus
• Athletes have more exposure to communal environments * more prone

The Immune System

First Line of Defense

• Skin and Mucous Membranes
• physical, chemical barrier
• don't distinguish pathogens
  
  

Skin

• sheds pathogens along with skin
• low pH *repels microorganisms
• glands in the skin secrete chemicals that slow the grow of bacteria
• [tears and saliva have enzymes that break down bacterial cells. Earwax traps microorganisms]
  
  

Mucous Membranes

• lining the respiratory, digestive, reproductive and urinary tracts
• Secretes mucous that traps pathogens which are coughed or sneezed away, destroyed in the stomach, excreted in urine or feces
• Digestive secretions including acids, kill many microorganisms
• vomitting can get rid of toxins or infectious agents
  
  

Second Line of Defense: Phagocytes & Macrophages, Inflammation, Defensive Proteins & Fever

Phagocyctes & Macrophages

• Phagocytes are white blood cells that attack and ingest invaders
• Macrophages are one type of phagocytic white blood cell that move throughout the lymphatic fluid, engulfing dead and damaged cells
• Enzymes inside the macrophage help destory the invader
• Macrophages clean up old blood cells, ddead tissue fragments and debris
• They release chemicals that stimulate the production of more white blood cells
• Mostly occurs within the lymph nodes
• If an invader is too big, white blood cells surround it and secrete digestive enzymes to irritate and destroy the invader
• natural killer cells extra white blood cells that circulate through blood and lymph destroying invaders
• attack tumour cells and viruses
• they release chemicals that break apart plasma membranes of invaders * they burst
• Fluid, dead cells and microorganisms = pus
• if pus can't drain, it becomes an abscess
  
  

Inflammation

• Responds to tissue injury
• Damaged cells release chemicals that stimulate special cells to release histamine
• Histamine promotes bigger blood vessels near the injury
• extra blood flow brings oxygen and nutrients for tissue to heal
  
  

Defensive Proteins

• Interferons (proteins prduced by virus infected body cells to help resist infection)
• When infected cells die, they release interferons (which bind to receptors on uninfected cells and stimulate the healthy cells to produce proteins that inhibit viral reproduction)
• Complement Proteins (circulate in the blood and help/complement other defence mechanisms)
• They coat the surface of microbes, making them easier for macrophages to engulf.
• They can poke holes in membranes causing them to break apart and increase inflammatory response
  
  

Fever

• normal range 97 - 99 F
• Macrophages release chemicals called pyrogens that cause fever
• Slight fever causes less bacteria to grow and increases rate of metabolic healthy cells
• Lets tissue to repair faster
• when the infection is controlled, the macrophages stop releasing pyrogens and body temperature goes back to normal
  

Third Line of Defense: Lymphocytes

• Specific Defense System has millions of white blood cells called lymphocytes
• they travel throughout the body by moving through spaces between cells and tissues
• transport via blood or lymphatic system
• triggered response by proteins or carbohydrates on the surface of pathogens or cells that have been infected
• Antigens molecules that stimulate and react to the immune system
• [found on invading viruses, bacteria, fungi, protozoans,worms, dust, pollen, transplanted tissues]
• When antigen is present in the body: production of 2 types of lymphocytes is enhanced 1. B cells 2. T cells
• they move through the ciruclatory and lymphatic system
• they are concentrated in the spleen and lymph nodes
• display specificity they recognize specific antigens
• Antigen Receptors proteins that make lymphocytes specific
• their shape fits perfectly into foreign molecule and they bind like a key into a lock
• B cells recognize small, free living organisms [bacteia and toxins]
• T cells recognize larger, body cells that have gone wild [cancer cells, cells invaded by viruses]
• B & T cells both help recognize and get rid or antigens but in different ways
• B cells secrete antibodies (proteins that bind and inactivate antigens)
• T cells directly attack invaders
  
  

Antibodies

• found in the blood, lymph, intestines and tissue fluids
• found in breast milk
• passive immunity transferring antibodies from mother to child (short term)
• Active Immunity Exposure to antigens and antibodies created by child
  
  
  

Allergy

• immune response that occurs when no pathogen is present
• body reacts to nonharmful substance as if a pathogen is present
• possible connection to allergies and vaccinations
  
  

Anticipating Infection

• Stem Cells produce lymphocytes
• bone marrow has a supply of stem cells
• Bone marrow cells can enable the bone marrow to produce blood cells over a life time
• Thymus Gland (stimulates T cells)