HBS 3.2 quiz

loasis

Also called African eye worm,

an infection that sometimes has no

or symptoms that appear months

after infection. Symptoms can

include the periodic appearance of

itchy but not painful swellings,

especially near joints, fatigue,

muscle and joint pain, and a worm

that crawls over the surface of the

eye in the conjunctiva.

conjunctivitis

Also called pink eye, an infection of

the conjunctiva that causes

inflammation. Eyes are red and itchy,

and may water or have a thick

discharge.

onchocerciasis

Also called river blindness, a

disease with symptoms

including impaired vision or

blindness caused by recurring

conjunctivitis, and infection of

the cornea and sclera, itching,

rash, or bumps under the skin

on the eyelid or around

eyelashes.

trachoma

An infection that can

cause vision impairment

and blindness when the

eyelid and eyelashes

scratch and damage the

cornea.

traumatic iridodialysis

An eye injury where the iris detaches from the

structure behind it (the ciliary body, which

includes the ciliary muscle and processes).

Signs and symptoms include an irregularly

shaped pupil, eye pain, and blurry or impaired

vision. Can result in glaucoma.

 immune system

protects the body from infectious disease. It is involved in tissue repair & protection against potential pathogens. 

skin

acts as a physical barrier between the external environment & the internal environment of the human body. It is salty & has hairs to catch/stop foreign materials & pathogens.

Mucous Membranes

compartments/layers that protect ocular, nasopharyngeal, respiratory, oral, gastrointestinal, and genitourinary mucosae. It provides defense against toxic agents that enter the body through the mucosal membrane. It comprises of epithelium covered by mucus.

spleen

controls the level of white blood cells, red blood cells (RBCs) & platelets (small cells that form blood clots). It screens the blood & removes any old or damaged RBCs.

thymus

is responsible for producing & maturing lymphocytes, or immune cells. These include T-cells, a type of WBC that defends the body from infections.

bone marrow

 is the spongy tissue inside bones that produces RBCs, platelets & WBCs. Lymphocytes, a type of white blood cell, are produced in the bone marrow & play an important part in the body's immune system.

tonsils

 like lymph nodes they help filter out germs that enter through your nose or mouth to protect the rest of the body from infection.

lymph nodes

filter substances that travel through the lymphatic fluid, & they contain lymphocytes (WBCs) that help the body fight infection & disease. There are hundreds of lymph nodes found throughout the body.

innate immunity

 is present before any exposure to pathogens & is effective from the time of birth. Involves nonspecific responses to pathogens & has a rapid response time.

innate immune response

 consists of a variety of non-specific features. It includes: Barrier defenses

• Phagocytosis

• Inflammation

• Antimicrobial peptides

• Natural killer cells

• Clotting

barrier defenses

Include the skin & mucous membranes of the respiratory, urinary, and reproductive tracts. Mucus traps & allows for the removal of microbes. Many body fluids including saliva, mucus, & tears are hostile to microbes due to the enzymes they contain. The low pH of skin & the digestive system prevents growth of microbes.

white blood cells

leukocytes, engulf pathogens in the body.

phagocytosis

WBCs engulf microbes and “membranes” them into a phagosome to isolate them, then that phagosome fuses with a (phago)lysosome to destroy the microbe with digestive enzymes and antimicrobial agents.

neutrophils

engulf and destroy microbes

macrophages

phagocytic cells

eosinophils

discharge destructive enzymes

dendritic cells

stimulate development of acquired immunity

blood clotting

stops bleeding and seals the wound

platelets (thrombocytes)

are small cell fragments that flow in the blood. When the skin is cut, they gather at the damaged site.

• They then release clotting factors, which initiate the blood clotting process.

adaptive immune response

consists of a variety of specific features. This system is responsive, & only kicks in when a pathogen enters the body. It is slow to react the first time it comes into contact with a pathogen, but will be quicker next time. 

It includes: 

• Lymphocyte & antibody production

thin skin

skin that has 4 layers of cells From deep to superficial, these layers are the: 

• Stratum basale

• Stratum spinosum

• Stratum granulosum

• Stratum corneum

thick skin

only found on palms of hands and soles of feet, has 5th layer stratum lucidum:

• Located between the stratum corneum and the stratum granulosum.

keratinocytes

cells in all layers except the stratum basale

dermis

It contains structures such as: 

• Blood vessels

• Lymph vessels

• Nerves

• Hair follicles

• Sweat glands

It is made of 2 layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts. These include:

• Papillary layer

• Reticular layer

papillary layer

 is made of loose, areolar connective tissue, which means the collagen and elastin fibers of this layer form a loose mesh. 

This superficial layer projects into the stratum basale of the epidermis to form finger-like dermal papillae. this layer also contains:

• Fibroblasts

• Adipocytes (low concentration)

• Small blood vessels (high concentration)

• Phagocytes

  • Defensive cells that help fight bacteria or other infections that have breached the skin.

• Lymphatic capillaries

• Nerve fibers

• Meissner corpuscles (touch receptors)

reticular layer

is composed of dense, irregular connective tissue. This layer is well vascularized and has a rich sensory and sympathetic nerve supply.  appears net-like due to a tight meshwork of fibers. Elastin fibers provide some elasticity to the skin, enabling movement. 

primary function of the skin

to act as a barrier, provides protection from Mechanical impacts

• Pressure

• Variations in temperature

• Microorganisms

• Radiation

• Chemicals

body temperature

the skin regulates this via

• Sweat

• Hair

• Changes in peripheral circulation

• Fluid balance (via sweat)

sebum

produced in the sebaceous glands, keeps the hair moist and flexible and prevents the drying out of the skin.

lymphatic system

• consists of organs, ducts, and nodes. It transports a watery clear fluid called lymph.  This fluid distributes immune cells and other factors throughout the body. It also interacts with the blood circulatory system to drain fluid from cells and tissues. 

lymphocytes

lymphatic system produces these  protect the body against antigens (viruses, bacteria, etc…) that invade the body. 

immune system cells

• All begin in the bone marrow, but become different types. 

• Differentiation is dependent upon need and cell signals. 

• B-cells, specifically plasma cells, produce antibodies. 

virions

comprised of an RNA or DNA genome surrounded by a protective protein coat and, in some cases, a lipid cover

viral replication steps

attachment, entry, uncoating, replication, assembly, maturation, release

attachment

The virus ______ to the surface of the animal host cell. The ________ of the virus to the host cell is highly specific to each virus. Viruses can _____to lymphocytes, monocytes, macrophages, and even epithelial cells. 

entry

The virus DNA _____ the host cell. This can occur in two ways: by endocytosis where the cell engulfs the virus, or by the virus fusing directly with the plasma membranes of the host cell.

uncoating

the breakdown or removal of the capsid of the virus, causing the virus genome to be completely released, exposing viral genes for transcription and replication.

replication

In the same way that our DNA encodes the information to manufacture our proteins, a virus’ genome acts as the instructions for the synthesis of virus proteins. The virus uses the host cell machinery to copy viral single-stranded RNA, double-stranded RNA, or single-stranded DNA depending on the virus, as well as proteins and additional genome copies.

assembly

Newly created virus parts self-_______ into new virions, intact and infective virus particles. The location of virion _______ depends upon the particular virus. It can take place within the nucleus of the cell, at the plasma membrane, or at a variety of intracellular membranes, such as the Golgi complex.

maturation

the virion has been in the process of forming, and if the cell was broken open, the virions would not be able to initiate infection of new cells. When ______ occurs, the final changes in structure of the capsid within an immature virion result in an infectious virus particle.

release

the cell host releases the new virions into the extracellular environment either through a process of lysis (which kills the cell) or by budding, where the virion can continue the cycle of infecting new cells.