Biology midterm #2
Terms
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- 4 types of tissues:
- Epithelial, Connective, Muscle, Nervous
- Epithelial
-
Lines the body’s surface, cavities, ducts, and tubes
-One free surface faces a body fluid or the environment
Simple epithelium consists of a single layer of cells
-Cell shapes: squamous, cuboidal, columnar
-Stratified epithelium is two or more layers thick
-Functions in protection, as in skin
-Cells in the layers may be - Connective
-
-support: Most abundant tissue in the body
Cells are scattered in an extracellular matrix
-Matrix is composed of collagen and/or elastin fibers in a polysaccharide ground substance
-Two major categories:
Soft connective tissues: loose; dense irregular; dense regular
-Specialized: cartilage, bone, adipose, blood - Muscle
-
movement: smooth, skeletal, and cardiac.
Muscles contract/shorten and then relax/lengthen; in this way they control movement of the body and its parts -
Nervous
Neurons
Neuroglia -
sensory: Detects stimuli, integrates information, and relays commands for response
Consists of excitable neurons and supporting neuroglial cells
Neurons: Excitable cells
Motor neurons relay messages from the brain to muscles or glands
Arrival of the impulse at the neuron endings triggers events that stimulate or inhibit adjacent neurons or other cells
Neuroglia: Constitute more than half of the nervous tissue; Protect and support the neurons, both structurally and metabolically - What do Tight junctions do?
- prevent leaks
- What do Gap junctions do?
- connect adjacent cytoplasms
- Adhering junctions
- cement cells together
- Epithelial tissue membranes
-
(epithelium + underlying connective tissues together)
Mucous membranes
Serous membranes
Cutaneous membrane (skin) - Connective tissue membranes
-
(no epithelium included in the membrane)
Synovial membranes (joints) - ORGAN SYSTEMS: integumentary system
- protect body from injury, dehydration, and some pathogens: control its temperature, excrete some wastes; receive some external stimuli
- ORGAN SYSTEMS: muscular system
- move body and its internal parts; maintain structure. generate heat (by increases in metabolic activities)
- ORGAN SYSTEMS: skeletal system
- support and protect body parts, provide muscle attachment sites, produce red blood cells, store calcium and phosphorous
- ORGAN SYSTEMS: nervous system
- detect both external and internal stimuli, control and coordinate responses to stimuli, integrate all organ system activities
- ORGAN SYSTEMS: endocrine system
- hormonally control body function, work with nervous system to integrate short-term and long term activities.
- Organ systems: lymphatic
- collect and return somae tissue fluid to the blood stream. defend the body against infection and tissue damage
- Organ systems: respiratory
- rapidly deliver oxygen to tissue fluid that bathes all living cells. remove carbon dioxide wastes from cells. help regulate pH.
- Organ systems: digestive
- ingest food and water. mechanically/chemically break down food and absorb small molecules into environment. eliminate food residues.
- Organ systems: urinary
- maintain the volume and composition of the internal environment. excrete excess fluid and blood-borne wastes.
- Organ systems: reproductive
-
female: produce eggs. after fertilization, afford a protective, nutritive environment of new individual.
male: produce and transfer sperm to the female.
for both, hormones influence other systems. - Homeostasis
-
Stable operating conditions in the internal environment (maintain stability in the volume and composition of extracellular fluid)
Brought about by coordinated activities of cells, tissues, organs, and organ systems
Requires the interaction of sensors, integrators, and effectors
NEGATIVE system: cancels or reverses an effect/response
POSITIVE system: intensifies the response by the system
The regulation of the amounts of water and minerals in the body. This is known as osmoregulation. This happens in the kidneys.
The removal of metabolic waste. This is known as excretion. This is done by the excretory organs such as the kidneys and lungs.
The regulation of body temperature. This is mainly done by the skin.
The regulation of blood glucose level. This is mainly done by the liver and the insulin secreted by the pancreas. - process of homeostasis
- receptor (free nerve-ending skin)--->integrator (ie. brain)---->effector(muscle or gland)--->(response to stimulus leads to change. change fed back to receptor. in negative system, response to feedback cancels out/ counteracts effect of original stimulus)--->back to beginning
- 5 microbes important to disease: bacteria
-
Unicellular and much smaller than eukaryotic cells; simpler in construction; haploid
Have complex cell walls that are important to the disease causing process and their resistance to antibiotics
Reproduce by binary fission (double contents and then split); some “sex†is possible
Metabolically bacteria are tremendously diverse (capable of metabolizing all natural compounds and many synthetic ones)
-very adaptable. - 5 microbes important to disease:Fungi
-
Yeast or mold forms;
eukaryotic;
haploid or diploid
Reproduce by budding or sexually via spore production
In nature, fungi are decomposers, responsible for most “turn-over†of organic material
Present in most warm environments; only 4 species are pathogenic for humans, the rest are opportunists - 5 microbes important to disease: Helminthes
-
Parasitic worms with complex life cycles that encompass adult feeding “worm†forms, eggs, and larval stages. Life cycles generally utilize more than one host and are acquired by humans from water, soil or food.
Reproduce via fertilization and release of eggs.
Environmentally restricted based on range of host species; usually not a problem for humans in the United States - 5 microbes important to disease: Protozoa
-
Unicellular eukaryotic microbes
larger than yeast cells,
lack cell walls,
diploid,
motile
Reproduce by binary fission or through complex life cycles involving different developmental forms
They are very diverse and are found in a variety of habitats, often preying on other microbes for food - 5 microbes important to disease: Viruses
-
Simplest microbes
Genome + protein
Genome can be DNA or RNA
Protein = capsid (helical or icosahedral)
Sometimes enveloped (with “spike†proteins)
Reproduce by parasitizing cells and forcing those cells to manufacture and assemble new viral particles. Can be very destructive – generally use the host cell up until it dies and lyses
ALL are parasites (obligate). Parasitize essentially every living cellular form on earth.
Viruses are not considered to be alive. - Pathogenesis
- the genetic ability to inflict damage to a host
- Virulence
- a quantitative assessment of pathogenicity (severity of symptoms)
- Resistance
- the ability of the host to prevent the establishment of the parasite/pathogen; highly variable
- Infection
- growth of microbes on/in the host
- Disease
- damage or injury to the host that impairs normal function
- Mode of transmission
- the method or process by which a pathogen moves from reservoir to host or from host to host
- major modes of transmission
-
Respiratory (droplets)
Airborne/Inhalation (particles)
Fecal-Oral
Physical Contact
Sexual
Contact with fomites (everyday objects)
Vector-borne from animals or insects
Vehicle-borne from water or food - microbe invasion
-
Animal bodies provide favorable environments for microbial growth (nutrients, protection, etc.)
Body is not a uniform “placeâ€; differs chemically and physically within any one individual and between individuals
Microbes must therefore be flexible to some extent to adapt but in the end microbes can’t colonize every place within us or every individual encountered
To have a shot at using the animal host, the microbe must first invade it – generally does this through one of the body surfaces exposed to the environment (internally or externally)
Where microbes enter is important, so is how many enter
Often stay near where they enter (local infections)
Systemic infections always bad news - Direct host to host transmission
- (involves actual direct contact): respiratory, direct contact, sexual, fecal-oral, biological vectors in vector-borne transmission
- Indirect host to host transmission
- (involves an intermediary between infected and uninfected): airborne/inhalation, fecal-oral in conjunction with fomites, vehicle-borne, mechanical vectors in vector-borne transmission
- Common Source pandemic
- infect large number from a single contaminated and commonly encountered source (often food or water); rapid rise to peak incidence, rapid decline; no host to host transmission
- propogated source pandemic
- one infected individual introduces infection to population; incidence shows slow rise to peak because transmission is from person to person following a chain defined by the microbe itself; can involve direct or indirect modes of transmission; not everyone traceable to same initial person
- Controlling Infectious Diseases
-
Increase the general health of ALL populations to increase overall community health; must be global venture
Control vectors and reservoirs to reduce potential exposure
Vaccinate or destroy domestic vectors, prevent wild to domestic transmission, eliminate insects, immunization, insecticides
Control general transmission of diseases through sanitation or reducing contact between infected and uninfected
Immunization to protect the susceptible; need to offer to adults and children globally (limited by technology and cost)
Surveillance and reporting to recognize early and cut down on transmission if at all possible (reportable diseases)
Eradication of pathogens - Functions of Bone
-
Interacts with muscle to enable movement
Supports and anchors muscles
Encloses and protects internal organs
Stores calcium and phosphorus
Produces blood cells - Long-Bone Development
-
Cartilage “model†of the bone provides a template for true bone formation
Growth occurs at the bone ends (epiphyses)
Epiphysis is separated from the bone shaft by a plate of cartilage
Plates are replaced by bone when growth ends
Bones held together by ligaments (joints) and tendons (muscle to bone) - Osteoblasts
- deposit bone
- Osteoclasts
- secrete enzymes that degrade bone
- The Axial Skeleton
-
Composed of:
Skull (cranial and facial bones, sinuses); protection of brain
12 pairs of ribs + sternum; protection organs, breathing, upper body scaffold
26 vertebrae (cervical, thoracic, lumbar, sacrum, coccyx); support and weight distribution
Intervertebral disks; shock absorbers and flex points - The Appendicular Skeleton
-
Composed of:
Pectoral girdle (scapula, clavicle); highly flexible
Arm, hand bones (30 separate bones total)
Pelvic girdle (6 fused bones); less flexible than pectoral girdle, meant to support weight of body
Leg, foot bones (femur, patella, tibia, fibula + 28 bones in the normal foot) - Fibrous joints
- short connecting fibers join bones
- Synovial joints
- move freely; ligaments connect bones
- Cartilaginous joints
- straps of cartilage enable slight movement
- Arthritis
-
Osteoarthritis (loss of cartilage covering ends of bones in joints); joint replacement possible
Rheumatoid arthritis (immunological self-attack) - Tendonitis
-
inflammation tendons, synovial membranes)
Carpal tunnel syndrome common in technology professions - Strains
- stretch/twist too far
- sprains
- tear
- dislocations
- bones out of the joint
- simple fracture
- crack
- complete fracture
- separation
- compound fracture
- fragmentation plus protrusion of bone through skin
- muscle fiber
- single muscle cell
- myofibrils
- make up muscle fiber
- Muscle Contraction
-
Sliding filament model
Myosin heads attach to actin filaments
Myosin heads tilt toward the sarcomere center, pulling actin with them
The concentration of calcium ions in the muscle determines whether myosin can bind actin
no ATP= muscle fatigue - Muscle tension
-
the mechanical force a contracting muscle exerts on an object
For a muscle to shorten, muscle tension must exceed the load that opposes it. The load may be the weight of an object or gravity’s pull on the muscle. - Isotonic contraction
- muscle visibly shortens; moves a load. Tension remains constant as the muscle changes length
- Isometric contraction
- Muscle does not change length. Tension is insufficient to move load
-
Slow/Red muscle
give example -
Many capillaries, high myoglobin
Contracts fairly slowly
Can sustain contraction
Example: back muscles - Fast/White muscle
-
Fewer capillaries, less myoglobin
Contracts quickly
Cannot sustain contraction
Example: muscles in the hand - Myopathies: Diseases of Muscle: Muscular Dystrophies
- several genetic based muscle-wasting diseases
- Myopathies: Diseases of Muscle:Metabolic
- endocrine or inflammatory myopathies
- Myopathies: Diseases of Muscle:Myositis
- inflammation and pain
- Myopathies: Diseases of Muscle:Neuromuscular diseases
- paralysis and others involving nerve damage and subsequent loss of muscle function
- Myopathies: Diseases of Muscle:trauma
- strains, bruising, etc. can lead to muscle stiffness or bleeding into the muscles
- Human Skin
-
Protects the body from injury, dehydration, UV radiation, and some pathogens
Helps control temperature
Receives some external stimuli
Produces vitamin D
Composed of epidermis and dermis overlying the hypodermis
Essentially forms the body “sack†containing bones, muscle and organs - Epidermis
- stratified epithelium that grows from bottom upward
- Dermis
-
dense connective tissue with many elastin and collagen fibers
Includes blood vessels, lymph vessels, and receptor endings of sensory nerves - Glands
-
derived from epidermal cells)
Sweat glands are controlled by sympathetic nerves and produce sweat (99% water, with dissolved salts, trace of ammonia)
Oil glands (sebaceous glands) produce secretions that lubricate and soften hair and skin; also kill many surface bacteria - Skin Infections:Bacterial diseases
- acne, necrotizing fasciitis, cutaneous anthrax, scalded skin syndrome
- Skin Infections:Fungal diseases
- cutaneous candidiasis, athlete’s foot, sporotrichosis, ringworm
- Skin Infections:Viral diseases
- herpes simplex, chickenpox (varicella and shingles), measles, rubella, smallpox, monkeypox, warts
- Skin Infections:Parasitic diseases
- leishmaniasis (protozoa), scabies (mites), lice
- The Digestive System/Gastrointestinal (GI) Tract
- long tube (~ 6.5 to 9 meters long if extended), lined with mucus-secreting epithelium, that moves materials one way – from the mouth to the anus
- functions of digestive system
-
Break up, mix, and move food material
Secrete enzymes to facilitate digestion
Digest (break down) food particles into smaller molecules
Absorb nutrients and fluids
Eliminate wastes and residues - Process of digestion
-
-teeth tear the food into small bits and mix the bits with saliva to start digestion
Food moves down the esophagus to the stomach: the stomach stores food, initiates protein digestion, controls food release to the small intestine
The small intestine further digests food and facilitates absorption.
ABSORPTION:carbohydrates and proteins are digested and then [B] absorbed. Fats are emulsified [C] and mixed with bile salts. Micelles form [D] which pass through the plasma membrane [E] into the cell where the move through into the internal environment of the body [F]. - Major Enzymes Needed for digestion: Carbohydrate Digestion
- salivary amylase (active in mouth and stomach), pancreatic amylase, disaccharidases (both active in small intestine)
- Major Enzymes Needed for digestion:Protein Digestion
- pepsins (stomach), trypsin and chymotrypsin, carboxypeptidase, aminopeptidase (rest active in small intestine)
- Major Enzymes Needed for digestion:Fat Digestion
- lipase (small intestine)
- Major Enzymes Needed for digestion:Nucleic Acid Digestion
- pancreatic nucleases, intestinal nucleases (both active in small intestine)
- Importance of the Liver in Digestion
-
Role in carbohydrate metabolism
Role in protein synthesis, disassembly
Forms urea from nitrogen-containing wastes
Assembles and stores some fats; forms bile to aid in fat digestion
Inactivates many chemicals (hormones, some drugs)
Detoxifies many poisons
Breaks down worn-out red blood cells
Aids immune response (removes some foreign particles) - Importance of Large Intestine (Colon) in digestion
-
absorbs some nutrients not absorbed by the small intestine (generally salts and water) and concentrates undigested materials for elimination as waste (feces)
-Proper movement of material through the colon is necessary for proper GI tract functioning
Constipation: feces remains “trappedâ€, water is absorbed, and the feces becomes hard and difficult to eliminate
Diarrhea: small intestine secretes more water and salts than the colon can absorb; feces is watery and hard to control - Nutritional Requirements for digestion:Complex Carbohydrates
-
(body’s main energy source)
Foods high in complex carbs usually high in fiber; promote colon health - Nutritional Requirements for digestion:Lipids
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(should be ~30% of diet)
Most fats can be synthesized but essential fatty acids must be obtained from food
Excess saturated fats can raise cholesterol level and contribute to heart disease - Nutritional Requirements for digestion:Proteins
-
Essential amino acids must be obtained from diet (8 out of 20)
Animal proteins are complete; supply all essential amino acids
Plant proteins are incomplete; must be combined - dietary essentials:vitamins
-
Fat soluble (excess accumulates in tissue): Vitamins A, D, E, K
Fat insoluble: B vitamins, Pantothenic acid, Folate, Biotin, Vitamin C - dietary essentials:Minerals
- Calcium, chlroide, copper, fluorine, iodine, iron, magnesium, phosphorus, potassium, sodium, sulfur, zinc
- body mass index-BMI
-
one indicator of obesity-related health risk as well as under-nutrition:
BMI = Weight (lbs) X 700
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Height (inches)2 - Malnutrition:
- body functions or development suffers due to inadequate or unbalanced food intake
- Under-Nutrition
- lack of food
- Obesity-related conditions
- Type 2 diabetes, Breast cancer, Heart disease, Colon cancer, Hypertension, Gout, Gallstones, Osteoarthritis
- Dietary Diseases and Disorders:Malabsorption Diseases
- Lactose intolerance, Cystic fibrosis, Crohn’s disease, Food allergies
- Dietary Diseases and Disorders:Eating disorders
- anorexia nervosa, bulimia