Week 4 - Physiology and immunology Flashcards by Gabriella Smith

What properties to gills have to efficiently obtain O2 from water?

Highly filamentous with gill lamellae = large surface area for gas exchange
Gills are highly vascularised - minimise distance for diffusion.
Have a counter-current exchange system

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How does the counter-current exchange system work in gills?

Blood flows in the opposite direction to water passing over the gills. So blood is always less saturated with oxygen than the water it meets.
Maintains a continuous pressure gradient between water and blood

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What is the main site of gas exchange on the gills?

Secondary lamellae (on the gill filaments)

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What is meant by ventilation?

Moving the respiratory medium over the exchange surface

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How do aquatic mammals ventilate their gills?

Buccal pumping, ram ventilation or jet propulsion

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What is buccal pumping ?

2 cavities expand alternately to pump water

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What is Ram ventilation?

Swimming fast with mouth partially open to ventilate gills

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What is jet propulsion?

Occurs in squid and octopuses:
Water is drawn into the mantle cavity, across the gills and then ejected through the siphon.

Form of movement and ventilation

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How does respiration occur in amphibian exchange surfaces?

Positive pressure breathing (forcing air in and out of lungs)
Respire across skin

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How does gas exchange occur in birds?

Air flows in 1 direction through parabronchi (small tubes) where gas exchange occurs.
Incoming air doesn’t mix with stale air (completely renewing the air with each breath)

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How does gas exchange occur in humans (starting with air through the mouth)?

Trachea
Bronchi
Bronchioles
Alveoli

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Do mammals have negative or positive pressure breathing?

Negative = pulls air into lungs, Exhalation is passive

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What is spirometry? What is the difference between capacity and volume ?

A technique that measures how much air you can inhale and exhale ( and what speed ).
Volume = a single measure of air
Capacity = All volumes added together

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What are 3 essential components of the circulatory system ?

Blood (circulatory fluid)
Heart (muscular pump)
Blood vessels (network of tubules)

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Do animals have an open or closed circulatory system?

Can have both

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What is the purpose of respiratory pigments? Give an example of one.

They bind to oxygen increasing the amount of O2 blood can carry- as by itself oxygen isn’t very soluble in liquid.
Example = haemoglobin

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If the partial pressure of carbon dioxide increased would oxygen binding to haemoglobin increase or decrease?

Decrease - Bohr effect

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Which group of animals have a single circulatory system?

Fishes, rays and sharks

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Which 4 groups of animals have a double circulatory system ?

Amphibians, reptiles, mammals and birds

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What is the order of the velocity of blood flow in vessels?

Arteries > Arterioles > Veins > Capillaries

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What is excitation contraction coupling ?

the process that links an electrical signal (excitation) to a muscle contraction

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What are heterotrophs ?

Animals that gain energy by eating other organisms

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What 3 nutritional needs to animals have?

Fuel for cellular work
Raw materials for biosynthesis
Essential nutrients

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4 stages of food processing ?

Ingestion
Digestion
Absorption
Elimination

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What is a suspension feeder? give an example

Sift small food particles from water - Whales

What are bulk feeders ? Give an example

Eat large pieces of food, tigers

What are substrate feeders? give an example

Live in or on their food source- earthworms and caterpillars

What are fluid feeders? Give an example

Suck nutrient-rich fluid from the living host - hummingbirds

What is a bolus?

Food shaped into a bolus by salivary and tongue to assist swallowing

What does the liver produce and how does that aid digestion?

Bile- contains salts and aids in the digestion and absorption of fats

What makes the small intestine efficient at absorption?

- Huge surface area - Highly folded surface with projections called villi - Highly vascularised nutrient-rich blood flow

What 4 cells do Crypt base columnar differentiate into?

- Paneth cells - Enteroendocrine cells - Goblet cells - Absorptive epithelial cells

What does the cecum connect?

The large and small intestine

Where does the waste travel to after the large intestine?

Cloaca

What does the pancreas secrete?

Proteases

Which component of the plant cells wall holds energy which the animal cannot digest themself ?

Cellulose

How do animals break down the cellulose?

Have a cecum which contains mutualistic communities of microorganisms that break it down

What is a ruminant?

A herbivorous animal with a 4 chambered stomach

What 4 chambers are in a ruminants stomach?

1. Rumen 2. Reticulum (Cellulose) 3. Omasum 4. Abomasum

What are osmoregulators?

They expend energy to control water uptake and loss in a hyper or hypo osmotic environment

What is the difference between hyperosmotic and hypoosmotic?

Hyper = high solute conc hypo= low

Why do marine mammals excrete highly concentrated urine?

Due to the amount of salt they ingest via the sea water and food they actively remove it to maintain their osmolarity.

What is nitrogenous waste?

Breakdown products of proteins and nucleic acids: Ammonia, urea, uric acid

What steps are involved in complex excretory systems?

Filtration Reabsorption Secretion Excretion

During reabsorption, which limp of the Loop of Henle are ions pumped out?

Ascending limb

How does ADH increase water reabsorption in the distal convoluted tubule and collecting duct?

It increases water reabsorption by triggering aquaporin insertion in the distal tubule and collecting duct

How does aldosterone increase Na+ reabsorption?

Aldosterone increases Na⁺ reabsorption by triggering more sodium channels and pumps in the nephron

How can Nitrogenous wastes be excreted?

Via ammonia, uric acid and urea

What is the difference between innate and adaptive immunity?

Innate immunity is non-specific and rapid- it relies on pathogen associated molecular patterns (PAMPs) which are recognised by Pattern Recognition Receptors (PRRs), whereas adaptive immunity is specific and slow - uses T-cells and B-cells.

What is the process of phagocytosis? Is it innate or adaptive?

Innate 1. Move towards pathogen 2. Make contact (binding of antibodies) 3. Engulf into a phagosome 4. Fusion with lysosome 5. Kill with toxic chemicals 6. Digest the remains

Which type of immunity (innate or adaptive) is found in all animals ?

Innate

Do invertebrates have innate or adaptive immunity?

innate

What is the difference between adaptive immunity in vertebrates vs invertebrates?

Invertebrates only have innate - vertebrates have innate and adaptive. Both have protein (complement system, antimicrobial peptides) and cell-mediated responses (Phagocytes). In vertebrates they produce antibodies as well, invertebrates don't

What is the complement system?

The attack and breakdown of cell walls

What are the 3 key features of the mammalian adaptive immune system?

1. Specificity 2. Memory 3. Tolerance to self and harmless antigens .

What is a small subsection of an antigen called that binds to the receptor?

Epitope

What are the 2 arms of the adaptive immune response?

Humoral - mediated by antibodies produced by B cells (B lymphocytes) Cellular immune response mediated by T cells (T lymphocytes)

How do B lymphocytes create an immune response?

1. They have membrane receptors that recognise a specific antigen 2. After interacting, B cell proliferates (multiplies rapidly) 3. Some cells differentiate into antibody-secreting B cells others into B memory cells

How do T- lymphocytes create an immune response ?

T lymphocytes produce T- cell receptors which recognise specific antigens, depending on the type of t cell different responses occur

What are the different types of T cell?

Helper T cells - provide signals to promote immune responses and assist B cells Cytotoxic T cells - directly kill target cells Memory T cells - remain in circulation

What is the definition of an antibody?

They are immunoglobulins that bind to specific molecular targets or antigens.

Describe the structure of an antibody

made of 4 chains : 2 heavy chains and 2 light chains lower region= constant upper region= variable