Bio 1002 Final Exam- Pomarico LSU

Homeostasis

Tendency of life to try and maintain the structure and regulate the internal environment

digestive

One of the biggest and most frequent homeostatic challenges an animal faces comes from the __________________ process.

unselective

The digestive system is ________________ in what crosses the intestinal wall and enters the cells.

Excretory System

Restores and maintains the proper internal regulation of these materials in the body despite differences in diet

Flame cells in flatworms

Most simple excretory system?

Flame cells

Hollow bulbs at the end of the network of tubes branching throughout the flatworm's body

-Water and dissolved wastes are filtered into the bulbs

Nephridia

-In nearly every section of earthworms and in mollusks.

-Function as simple kidneys.

-Wastes and nutrients collected from the blood and tissues fills the coelom

Nephrostomes

Funnel-shaped openings where coelomic fluid enters the nephridia.

1. Excretion of cellular waste products

2. Regulation and maintenance of body fluid composition (ions, water, nutrients)

3. Secretion of hormones

3 Major Functions of the Excretory System (mammals)

Kidneys

-Filters blood and produces urine

-Complex organs that resemble a dense collection of nephridia

-Paired, bean-shaped organs

-About 5x3x1 inch

-Have a large surface area where nutrients are selectively reabsorbed and wastes and some water are left behind to form urine

-Regulates water absorption

Urea

A compound that removes ammonia from the blood

Formation and excretion of urea

1. Proteins in food are digested

2. Amino acids are carried in the blood to body cells

3. Amino acids become ammonia (toxic) and simpler molecules

4. Ammonia becomes urea, which is less toxic.

5. Urea is carried in the blood to the kidneys

6. In kidney nephrons, urea is filtered into the urine.

kidneys; urinary system

Excretion in humans and other vertebrates is accomplished by the ____________ and the ______________ _______________.

arteries; veins

Unfiltered blood enters through the renal _____________ and filtered blood leaves through renal ____________.

Ureter

Passes urine by peristalsis to the bladder

Bladder

Hollow muscle that stores and collects urine

Urethra

Where urine is emptied

sphincter

The retention of urine in the bladder is controlled by 2 _______________ muscles.

involuntarily; receptors in the bladder walls trigger reflexive contractions

The first sphincter opens ____________________. Due to...

voluntarily

The second sphincter opens _____________________.

pint

The average adult bladder can hold about a ________ of urine.

Urination

-Both sphincter muscles at the bladder's base relax

-The bladder contracts, forcing urine down the urethra

Stretched receptors

What senses bladder fullness?

Nephrons

Where urine forms in the solid outer layer of the kidneys

1. Cortex

2. Medulla

2 parts of the outer layer of the kidneys

Renal Pelvis

Hollow inner chamber of the kidneys that funnels the urine into the ureter.

1. Glomerulus

2. Bowman's capsule

3. Tubule

3 parts of a nephron

Glomerulus

A filter for blood

Bowman's Capsule

Collects the filtrate (fluid filtered from the blood)

1. Proximal Tubule

2. Loop of Henle

3. Distal tubule that leads to collecting duct

3 parts of the tubule (in nephron)

Arterioles

1. _____ conduct blood to each nephron

glomerulus

2. Within Bowman's capsule the arteriole subdivides into a capillary network called the _____

permeable

3. The glomerulus capillary walls are _____ to water and dissolved substances

watery

4. The _____ filtrate, resembling blood plasma minus the proteins, is collected in Bowman's capsule for transport through the nephron

concentrated

5. The blood leaving the the glomerulus in the arteriole is much more ______, containing blood cells, proteins and fat droplets too big to be filtered out.

capillaries

6. These arterioles then branch into smaller highly porous _____ that surround the tubule.

Tubular reabsorption

7. ____ ____ occurs as the blood reabsorbs water and nutrients from the filtrate.

secreted

8. Any waste materials remaining in the blood are actively _____ into the tubule.

osmosis

9. During its passage through the collecting duct, additional water leaves the filtrate by ____ until the urine reaches equilibrium with the highly concentrated surrounding fluid.

350

How many times do the kidneys filter a human's blood a day?

Death

What happens when the kidneys fail?

45; reabsorbed; osmosis

Over ____ gallons of water enter the Bowman's capsule daily. Most is ___________________ through _______________.

Antidiuretic Hormone (ADH)

-AKA vasopressin

-Regulates how concentrated urine becomes and how much water is reabsorbed

-ADH levels in the blood increases permeability of the distal tubule and collecting duct to water.

-Made by the hypothalamus in response to receptor cells there (that monitor the concentration of the blood) and in the heart (monitor blood volume)

more

When the concentration of blood rises or blood volume falls, __________ ADH is released.

-Causes dilution in the blood and increase in blood volume

-The bladder fills faster and the urine is much less concentrated.

What does drinking beer do?

1. External barriers

2. Innate immune response (non-specific)

3. Adaptive immune response (specific)

3 lines of defense against microbial attack

1. Skin

2. Mucous Membranes

2 External barriers

Skin

A physical barrier to microbial entry and an inhospitable environment for microbial growth.

-Dry, dead cells at the surface

-Sweat and sebaceous glands secreting acids and natural antibiotics like lactic acid

Mucous Membranes

Well defended.

-Mucus secretions have antibacterial enzymes like lysozyme. Mucus traps microbes entering through nose or mouth.

-Membrane cilia sweep up mucus and microbes and they are coughed or sneezed out of the body

-If microbes are swallowed, stomach acid and protein-digesting enzymes destroy them.

1. Phagocytic cells

2. Natural killer cells

3. Inflammatory response

4. Fever

4 Nonspecific internal defenses

Phagocytic Cells

-White blood cells macrophages in the extracellular fluid.

-Amoeboid cells that destroy invading microbes by engulfing them by phagocytosis.

Natural killer cells

-White blood cells that destroy body cells that have been infected by viruses or "compromised" in any other way.

-Recognize and kill cancer cells

-Cause holes or pores to form in the surface of the "infected" cell

Inflammatory Response cause

Large scale microbial invasion through a wound that has caused tissue damage.

How inflammatory response works (8 steps)

1. Damaged cells release chemicals that stimulate mast cells

2. Mast cells release histamine into the wounded area.

3. Histamine increases blood flow to the wound by relaxing arterioles and making capillary walls leaky.

4. The wound becomes red, swollen, and warm

5. Other chemicals attract macrophages (wbc's) which engulf bacteria, dirt, and tissue debris

6. Blood clotting occurs, "walling off" the wounded area

7. As the wbc's die, they collect as pus

8. Any microbes that escape into the bloodstream are eaten by wbc's.

Fever

A response to microbes that succeed in establishing a major infection. Severe fevers are dangerous, but low-grade fevers (100-102 degrees) are beneficial.

-Shuts down microbial reproduction

-Enhances the body's own fighting abilities

How fever works (3 steps)

1. The set-point in the hypothalamus of the brain is turned up by certain hormones called endogenous pyrogens that are released by certain wbc's when disease organisms invade the body.

2. The new set point triggers shivering, increased fat metabolism, and the feeling of coldness.

3. The pyrogens cause other cells to reduce iron and zinc concentrations in the blood.

Endogenous Pyrogens

Hormones released by certain white blood cells that turn up the set point in the hypothalamus and causes fever.

Lymphocytes

B cells and T cells (white blood cells) (arise from bone marrow)

Immune Response

Reacts one one SPECIFIC type of microbe and provides future protection against this microbe type but not others

-B cells and T cells

1. Recognizing the invader

2. Launching a successful attack

3. Remembering the invader to ward off future attacks

The overall immune response that results in a 3 step process:

1. Antibodies made by B cells

2. T-cell receptors that are made on the surface of T cells

2 types of proteins accomplish the function of recognition:

Antibodies

Y-shaped proteins made of 4 peptide chains. The chains are arranged in pairs consisting of 1 large (heavy) chain and one small (light) chain on each side of the Y.

Constant Region

Stem of the Y. Pretty much the same in all antibodies.

Variable Region

Tips of the Y. Different in different antibodies.

-The specific bonding site of antigens.

Antigens

Any substance that is recognized/bound during the specific immune response

1. Humoral immunity

2. Cell-mediated immunity

The immune system can mount 2 types of attack:

B; free antibodies

Humoral immunity by ___ cells is mediated by _________ _________________ in the blood stream.

How humoral immunity works: (3 steps)

1. Antigens in the bloodstream encounter B cells, each with a specific surface antibody

2. The B cells with the appropriate antibody bind to the antigen

3. The antigen-antobody binding triggers clonal selection

Clonal selection

Division of B cells in humoral immunity

1. Plasma cells

2. Memory cells

What cell types do humoral immunity result in?

The antibodies circulating in the bloodstream can cause 4 effects:

1. Neutralization of toxins by binding with them

2. Promotion of phagocytosis by coating the antigen

3. Agglutination of antigens due to each antibody being able to attach to more than one antigen molecule. This seems to enhance phagocytosis by wbcs.

4. Complement reactions where the antigen-antibody complex causes the release of other blood proteins that can destroy invading or compromised cells.

Cell-mediated immunity

-By T cells.

-Kills the target cell immediately.

-Can destroy the body's own cells when they become cancerous or infected with viruses.

How cell-mediated immunity works:

When T cell receptors bind an antigen, the T cells divide rapidly, producing 2 types of cells (effector cells and memory cells)

Effector Cells

Attack cells but do not release antibodies in the bloodstream.

1. Helper T cells

2. Killer (cytotoxic) cells

3. Suppressor Cells

Effector Cell types (3)

Helper T cells

Releases interferon that stimulates cell division and differentiation in killer T cells and B cells

AIDS

Disrupts this process by destroying helper T cells

Killer T cells

Bind to antigens on the surface of "enemy" cells and release proteins that disrupt the plasma membranes of those "enemy" cells.

Suppressor T cells

Appear after the "enemy" has been conquered to shut off the immune response in B cells and killer T cells

Memory T cells

Protect the body against future infections by retaining immunity to future infection

Plasma B and killer T

_____________ ____ and _____________ ____ immediately fight infection but only live for a few days.

B and T Memory

____ and ____ ________________ cells survive for years.

Protects you from the same enemy in the future

What does winning the fight do?

Memory cells when there is reinfection

-They recognize the antigen and multiply rapidly to make huge populations of plasma B cells and killer T cells to evoke a 2nd immune response

-Respond faster than the B and T cells that originally made them.

-React so quickly that often there are no noticeable symptoms of the reinfection

Allergies

An exaggerated immune response to something that should not require an immune response

How allergies work: (4 steps)

1. An allergen enters the bloodstream and a B cell recognizes it as a foreign antigen

2. The B cell proliferates, making plasma cells that pour out IeG (allergy antibodies) into the bloodstream

3. The antibodies bind to histamine-containing "mast cells" in connective tissue

4. When the mast cells make contact with the allergen, they release their histamine, causing increased mucus secretion, leaky capillaries, and other symptoms of inflammation ("hay fever")

Antihistamines

Block some of the histamine effects

Vaccine

A substance used to create an intentional exposure to antigens to produce immunization

Pathogen

Another name for an infectious agent

Microbe

Another name for a small infectious agent

1. in or on the cell membrane

2. Inside the cell (in the cytoplasm or more often in the nucleus

Where do target cells have receptors?

Endocrine System

Uses hormones to communicate either locally (cell-to-cell) or over a greater distance

Distance communication

-Usually a greater number of cells are affected

-The communication occurs at a slower speed

-The message is of greater duration

Endocrine

Many hormones in mammals are produced by _________________ glands.

1. Endocrine

2. Exocrine

2 Main types of glands in mammals

Endocrine Glands

-"Ductless glands"

-Consist of clusters of hormone-producing cells embedded within a network of capillaries

-Secrete hormones into the interstitial fluid surrounding the capillaries

-The hormones enter the capillaries by diffusion and are carried to other parts of the body

1. Peptide hormones

2. Modified amino acids

3. Steroids

4. Prostaglandins

4 Classes of Animal Hormones

Prostaglandins

Local hormones which are modified fatty acid. They have a number of diverse roles in humans and are the subject of a significant amount of current research.

-Bind to surface receptors on the cell membrane (water soluble but not lipid soluble. cannot cross the cell membrane)

-Must react with protein receptors on the cell surface, which can then trigger rapid short-term internal cellular changes via a second messenger

Second Messenger

Transfers the information from the first messenger (the hormone) to target molecules in the cell.

Ex: c-AMP

c-AMP

Type of second messenger that activates cellular enzymes