Exam 1: Animal Tissues, Circulatory System, Respiratory System, Immune System & Digestion

Exam 1 includes materials from WK 1 Sept 23rd until WK 3 Oct 9th

Why do more complex animals have highly folded or branched internal surfaces?

To increase surface area for efficient exchange of gases, nutrients, and wastes when the outer skin is no longer large enough to support the entire body mass.

What are cell junctions? What do they do?

Cell junction is a specialized protein structure in the plasma membrane that connects neighboring cells to each other, or connects a cell to the extracellular matrix.

What are the 4 tissue types? Name their functions as well as the subtypes of each.

1. Epithelial Tissue

• Function: covers body surfaces and lines the internal cavities and hollow organs

• Subtypes: squamous, cuboidal, columnar and the number of layers such as simple or stratified

2. Connective Tissue

• Function: Connects, binds, supports, protects, insulates, and cushions other tissues and organs

• Subtype: Broadly divided into connective tissue proper (adipose; fat), supporting connective tissue (cartilage, bone), and fluid connective tissue (blood, lymph)

3. Muscle Tissue

• Function: Contracts and shortens to generate force, body movement, pumping blood and substances through internal organs

• Subtypes: Skeletal Muscle (strained, voluntary; attached to bones to move skeleton), Cardiac Muscle (strained, involuntary, branched with intercalated discs; found in the heart to pump blood), Smooth Muscle (non-striated, involuntary, spindle-shaped; found in the walls of hollow organs, blood vessels, and digestive tract)

4. Nervous Tissue

• Function: Detects stimuli, processes information, and rapidly transmits electrical and chemical signals across our body

• Subtypes: Neurons (responsible for generating and conducting electrical signals such as sensory and motor)

What is the extracellular matrix?

ECM is a complex, non-cellular networks of proteins, enzymes, and carbohydrates that surrounds, supports, and gives structure to cells and tissues in our body

What is homeostasis? Describe negative and positive feedback and be able to recognize examples of each.

• Homeostasis is when an organism is able to maintain a steady or balanced state (e.x. body temperature or blood sugar)

• The negative feedback is when a process reverses a change away from a set point, bringing the system back to normal balance (e.x. negative feedback loop)

• The positive feedback is when a process accelerates the initial change rather than reversing it, pushing the system further away from the starting point (e.x. childbirth, labor)

What is open circulation? Hemolymph?

A transport network where the circulating fluid leaves blood vessels and flows directly into body cavities to bathe internal organs.

What is closed circulation? How does it differ from open circulation? What are the advantages to each?

• Closed circulation uses more energy and is when blood stays inside a continuous network of vessels (arteries, veins, and capillaries)

• Differs from open circulation because open requires lesser energy

• Advantages of Closed circulation is high efficiency and active lifestyles

• Advantages of Open circulation is it requires less metabolic energy, is simple, and suited for smaller bodies such as insects and snails

Explain the difference between single and double circulation. How does double circulation differ between amphibians, reptiles & mammals.

Difference between Single & Double circulation:

• Is in single, blood passes through the heart once during each complete circuit (e.x. founded in fish it goes from heart→gills/respiratory organs→ body tissues→heart).

• Whereas in doubles blood passes through the heart twice during each complete circuit of the body (splits into 2 distinct loops such as Pulmonary which carries blood between heart and lungs/skin to get oxygen, and lastly the Systemic circulation which carries oxygen rich blood from heart to the rest of the body tissues and returning oxygen-poor blood back to the heart).

Be able to identify structures in the heart and trace the flow of blood.

What is systole? Diastole? How do they work together to move blood?

• Systole is when the heart muscles contract/squeeze the hearts chamber to push blood out and Diastole is the chambers heart relaxing its muscle as it expands to fill in blood.

• They work together by acting as a “push and fill” pump system because of the pressure changes happening to the hearts chambers is by the systole and diastole phases.

How is circulation different in a fetus (generally)?

• Fetal circulation is different for example, compared to an adults circulation because a fetus relies on the placenta for oxygen and nutrients from the mother because its own lungs and digestive systems are still developing.

What is the difference between arteries, veins and capillaries? What do they do and how does their structure (form) fit their function?

• Difference between these three blood vessels is the direction of blood flow, blood pressure level, and their physical wall structure.

• Arteries function is to deliver blood away from the heart to the lungs so it can pick up fresh oxygen.

• Veins function is to return the blood back to the heart by collecting oxygen depleted blood and returning it safely to the heart under low pressure.

• Capillaries function is to exchange nutrients and waste because they form a massive network touching every cell of our body by being responsible for delivering (oxygen, glucose, vitamins, and amino acids) and collecting (carbon dioxide and waste products).

What is blood pressure? What influences blood pressure?

• Blood pressure= the force of circulating blood pushing against the walls of your arteries.

• Blood pressure is influenced by our activity, health, and the environment.

• It can often times also be from lifestyle, stress, age/genetics.

What is in blood? Describe the main functions of the different components of blood.

• Inside blood there is 1. Plasma (about 55% of blood), 2. Erythrocytes (RBC about 45% of blood), 3. Leukocytes (WBC about 1% or less of blood), and 4. Platelets (about 1% or less of blood)

• Main functions→ 1. Transport (delivers oxygen, nutrients, and hormones), 2. Removal (carries away CO2 and metabolic wastes), 3.Protection (defends against infections and diseases), 4.Regulation (helps control body temperature, fluid balance, and pH levels), 5.repair (seals damaged blood vessels)

Describe the respiratory surfaces that animals use.

4 Types Animals Use:

1. The body surface/skin (oxygen & carbon dioxide diffuse directly across outer skin or cell membranes)

2. Gills (specialized for aquatic environments, their thin filaments and lamellas maximize surface area)

3. Tracheal system (a network of air tubes branches throughout body and carries oxygen directly to cells)

4. Lungs (folded or pocketed respiratory surfaces protected inside our body)

What is countercurrent exchange?

• Countercurrent exchange= a biological and physical mechanism where two fluids or substances flow in opposite directions past each other. Allows the transfer of heat, oxygen or solutes (like salt).

Know the basic anatomy of the respiratory system.

How do the structures of the alveolus and the capillary facilitate gas exchange?

• Alveolus and Capillaries work together to make gas exchange fast and efficient

• This through thin walls (aleveoulus= single layer epithelial cells, & capillaries= endothelial cell walls), having a large surface area, dense capillary, moist lining and the concentration/pressure of the gradients

What is positive pressure breathing vs negative pressure breathing? Which do mammals do?

• Positive pressure breathing= air actively forced or pumped into the lungs at a higher pressure than outside air.

• Negative pressure breathing= chest cavity expands when your diaphragm and rib muscles contract. this expansion than lowers the air pressure inside your lungs, below the outside air pressure.

• Mammals use negative pressure breathing.

How is breathing regulated in humans (generally)?

• It’s regulated automatically by the brainstem which is continuously monitoring the bodies chemical needs and will adjust to the rate and depth of respiration without having to use our conscious effort.

What is cooperative binding of oxygen to hemoglobin? How does this relate to the Bohr shift? How does the Bohr shift facilitate oxygen offloading in metabolically active tissues?

• Cooperative binding= the process where the binding of one oxygen molecule to one of hemoglobins four heme subunits causes a structural shift (from low affinity T-state to the high affinity R-state), making it progressively easier for additional oxygen molecules to bind.

How is carbon dioxide transported?

• Is transported from the body’s tissue to the lungs through the bloodstream.

What is the difference between innate and adaptive immunity? What animals have which system?

Difference:

• Innate is a fast, non-specific defense response present from birth, while Adaptive immunity is a slower, highly specific defense that builds itself to remember the pathogen and will become stronger to fight it off.

What are the physical barriers of the innate immune system? What are the internal defenses?

• Physical barrier of innate immune system is they act as the body’s first line of defense to block and trap pathogens before they can enter. (What does this mean? → our body has built in outer shield to keep germs out so you don’t get sick in the first place).

• Internal defense once the pathogens break through our physical barriers is 1. phagocytes (white blood cells that engulf & digest invading microbes), 2. lymphocytes (identifies & destroy your own infected or cancerous cells), 3.inflammation (chemical response that dilates our blood vessels, brings heat, swelling, and a rush of immune cells to the injury site), 4.complement system (blood proteins that punch in bacterial cell walls and mark them for destruction), 5. cytokines & interferons (chemical warning signals released by cells to block viral replication and coordinate the attack), 6. fever (an elevated body temperature that slows down germ reproduction & accelerates tissue repair).

What is the inflammatory response and how is it carried out by the innate immune system?

• Inflammatory response= a rapid, protective physiological reaction of the body to tissue damage, toxins, or microbial invasion

• It is carried out by the innate immune system by performing inflammatory responses through a well-coordinated sequence of cellular and molecular events.

What is antigen? Antigen receptor? Epitope?

• Antigen= protein, polysaccharide, or toxins that the immune system recognizes as foreign or self-reactive, triggering an immune response

• Antigen receptor= specialized protein molecule on the surface of immune cells (B-cells and T-cells) that binds directly or indirectly to an antigen to start an immune system reaction

• Epitope= tiny patch, or region on the antigen that actually makes physical contact with the antigen receptor or antibody

What do T cells do? Explain how the MHC molecule facilitates T cell function.

• T-cells directly detects and kill cells infected by viruses, they than release chemical signals (cytokines) to activate other immune cells, it than suppress and controls our immune responses to prevent autoimmune reactions/disease, lastly if the same pathogen returns our body has the virus in memory so if it were to return it’ll launch an aggressive response.

How do B cells and T cells differ? How does the structure of their antigen receptor differ?

Differences:

• B-cells mature in the bone marrow, while T-cells start in the bone marrow but travels to the thymus (a small organ located in upper chest, behind breast bone infant of heart) to mature.

• Structure of their antigen differ by B-cell’s being Y-shaped (made up of 4 polypeptide chains, 2 identical antigen binding regions per receptor) while T-cells are linear (not Y-shaped, usually made up of 2 polypeptide chain, has one antigen binding region)

What is an antibody? How are B cells and plasma cells related? What is clonal selection?

• Antibody= is a protective protein made by the immune system.

• B-cells and plasma cells are related because plasma cells are a version of mature B-cells that have transformed into active “antibody factories.”

• Colonial selection= is a process where specific foreign antigen matches and activates only the particular B or T-cells that will have the right receptor for it.

How is antibody diversity generated?

Antibody diversity is generated by 4 steps, 2 main phases:

• Phase 1 (Before antigen contact): Recombination through RAG enzymes randomly cutting and pasting different V, D, and J gene segments together. Junctional diversity where TdT enzymes randomly adds or deletes nucleotides. Combinatorial pairing where unique heavy chain randomly pairs up with any light chain.

• Phase 2 (After antigen contact): Somatic hypermutation where AID enzyme introduces rapid point mutations into the binding regions. B-cells with highest binding strength are than selected to survive.

Explain the difference between the primary immune response and the secondary immune response of the adaptive immune system. How is this used in vaccination.

• Differences between primary and secondary immune responses is speed, strength, and the type of cells involved.

• Used in vaccination by building our immunity without making you sick.

What is passive immunity?

• Passive immunity= a type of short term protection where a person receives ready-made antibodies from an external source rather than producing them through their own immune system.

Explain the basics of an ELISA.

• It is a laboratory test used to detect and measure specific proteins, antigens, antibodies, or hormones in a fluid sample using targeted antibody- antigen binding and an enzyme driven color reaction

Why do we eat? What are the essential nutrients? What’s the difference between vitamins and minerals?

• We eat to give our body energy and repair itself to grow, survive and function properly

• The essential nutrients are macronutrients (includes carbohydrates for energy, proteins for muscles/hormones, and fats/lipids for energy storage and cell membranes)

• Difference between vitamins and minerals are their chemical makeup and origin

What are the stages of food processing? What’s the difference between digestion and absorption?

Stages of food processing:

1. Ingestion

2. Digestion

3. Absorption

4. Elimination

Difference between digestion and absorption:

• Digestion= the breakdown process

• Absorption= body takes tiny nutrients from your digested food and moves them into your blood, so cells can use for energy

What is the difference between intracellular digestion and extracellular digestion? Gastrovascular cavity vs alimentary canal?

Difference:

• Intracellular= occurs inside the cell using lysosomal enzymes

• Extracellular= occurs outside the cells within a specialized body cavity or digestive tract

Difference:

• Gastrovascular cavity= has a single opening that acts both the mouth (for ingestion) and anus (for elimination/digestion)

• Alimentary canal= has two openings (a separate mouth and anus) forming a continuous tube

What are the main functions of the organs in the digestive tract and accessory organs?

• Main functions in digestive tracts are breaking down food, absorbing nutrients and eliminating waste. And with accessory organs they supply digestive juices and support chemical processing.

What happens in the mouth & esophagus?

• Mechanical and chemical digestion begins, and food is safely transported to the stomach.

What is chyme & why are sphincters needed in the stomach? What do chief cells and parietal cells do and where are they found?

• Chyme= is a thick, semi-fluid mass of partially digested food mixed with stomach acid and digestive juices

• Sphincters are needed in stomach because it helps open to let food in and stays closed the rest of the time to prevent harsh stomach acids flowing back up to the esophagus causing heartburn or acid reflux (can be painful)

What happens in the small intestine?

• Finishes digesting food and absorbs 90% of it’s nutrients and water into your bloodstream

Where does digestion happen and with what enzymes? How is fat digested?

• Digestion happens along the gastrointestinal tract (specifically mouth, stomach, and mainly small intestines such as our pancreas and liver)

• Fat is digested through 4 steps (initiation→ mouth/stomach, emulsification→ small intestine, enzymatic breakdown→ released by the pancreas, and absorption→ fatty acids and monoglycerides combine)

What is chylomicron?

• Large, triglycerides that are rich lipoprotein particles produced by the small intestine that transports the dietary fats and fat soluble vitamins through our lymphatic system into the bloodstream.

What is a ruminant and how do they digest plants? Why are symbiotic bacteria important in digestion in cows and in people?

• Ruminant is a herbivore (e.x. cows, sheep, deers, or goats) that digests plant based food through a specialized multi-chamber stomach and process.

• Important for digestion in cows because symbiotic bacteria living in the rumen are essential for survival.

• Important for humans because we are monogastric (single chambered stomach) it helps our body digest fiber, make vitamins, protect against sickness and trains our immune system.