Chapter 15 - We Are Not Alone Flashcards
The human body exists in a state of _______ ___________ with microorganisms
Dynamic equilibrium
Many interactions between human body and microorganisms involve the development of ________
Biofilms
____________ of the body involves a constant “give and take”
Colonization
Microbes that engage in mutual or commensal associations
Normal (residential) flora, indigenous flora, microbiota
Causes infection
Pathogen
Its in tissues and organs and causes disease
Infectious disease
Most areas of the body in contact with the _______ ___________ harbor resident microboes
Outside environment
What are microbe-free?
Internal organs, tissues, and fluids
Microbes that occupy the body for only short periods
Transients (we pick these up)
Microbes that become established
Residents (normal flora)
What are the sites that harbor a normal flora?
- Skin and its contiguous mucous membranes
- Upper respiratory tract
- Gastrointestinal tract (various parts)
- Outer opening of urethta
- External genitalia
- Vagina
- External ear and canal
- External eye (lids, lash, follicles)
What are all the internal tissues and organs that are sterile (microbe-free)
- Heart and circulatory system
- Liver
- Kidneys and bladder
- Lungs
- Brain and spinal cord
- Muscles
- Bones
- Ovaries/testes
- Glands (pancreas, salivary, thyroid)
- Sinuses
- Middle and inner ear
- Internal eye
What are the fluids within an organ or tissue that are sterile (microbe-free)
- Blood
- Urine in kidneys, ureters, bladder
- Cerebrospinal fluid
- Saliva prior to entering the oral cavity
- Semen prior to entering the urethra
- Amniotic fluid surrounding the embryo and fetus
Bacterial flora benefit host by preventing overgrowth of harmful microbes
RESIDENT FLORA
Microbial antagonism
Endogenous infections
______ and contents are normally sterile and remain so until just before birth
Uterus
Breaking of fetal membrane exposes the infant; all subsequent handling and feeding continue to introduce what will be ______ _____
Normal flora
____ is the largest and most accessible organ
Skin
What are two cutaneous populations?
- Transients
2. Residents
The GI tract is a long hollow tube, bounded by what?
Mucous membranes
Variations in flora distribution due to varying conditions like what?
pH, oxygen tension, and anatomy
Oral cavity, large intestine, and rectum harbor which flora?
Substantial flora
What has the most diverse and unique flora of the body?
Mouth
The mouth has numerous adaptive ______
Niches
What is the bacterial count of saliva?
5x10^(9 cells) per milliliter
Has complex and profound interactions with host
Flora of large intestine
10^8-10^11 microbes per gram of feces
Large intestine flora
Intestinal environment favors _________ bacteria
Anaerobic
Intestinal bacteria contribute to intestinal ____
Odor
Oral streptococci are the:
First organisms to colonize
Nasal entrance, nasal vestibule, anterior nasopharynx
S. aureus
Mucous membranes of nasopharynx
Neisseria
Tonsils and lower pharynx
Haemophilus
What ate the sites that harbor microflora?
Male and female genitourinary tract
Changes in physiology influence the composition of the ______ _____
Normal flora
- Vagina (estrogen, glycogen, pH)
Normal flora is essential to the ______ of humans
Health
Flora create an environment that may prevent infections and can enhance host ________
Defenses
Antibiotics, dietary changes, and disease may:
Alter flora
Introducing known microbes back into the body
Probiotics
What are the major factors in the development of infection?
Portal of entry => Adhesion => Invasion => Multiplication => Infection of target => Disease => Portal of exit
Influenza virus, plague bacillus, malarial protozoan
True pathogens
Pseudomonas sp and Candida albicans
Opportunistic pathogens
Cause infection in perfectly healthy people
True pathogen
Only cause disease when host defenses are down
Opportunistic pathogen
More virulent, more pathogenic, refers to the degree of pathogenicity
Virulence