IB Biology HL Topic 11 - Animal Physiology

Osmoregulation

the control of solute concentrations and water balance

Osmoconformers

An organism that allows its internal salt concentration to change with the salinity of the surrounding water; always matches external conditions

Nitrogenous waste

Waste products of metabolism that must be excreted; ammonia (fish), urea (mammals) or uric acid (birds and insect)

Malpighian tubules

An organ that is unique to insects, empties into digestive tract and removes nitrogenous wastes from the hemolymph

Hemoplymph

Circulating system of fluids in insects, akin to the blood system in humans; contains uric acid, amino acids, water etc

Hindgut

Selective reabsorption of useful substances in insects; uric acid and some water passes through to the rectum for excretion

Cortex (kidney)

outer, dark layer of the kidney containing the majority of the nephron

Medulla (kidney)

inner portion of kidney, lighter colour where the loop of henle and collecting duct leads to

Renal artery

artery that carries blood to the kidney; higher glucose, oxygen, urea, toxins, drugs, salts; less CO2; variable concentrations

Renal vein

vein that carries blood out of the kidney; higher CO2; lower glucose, oxygen, urea; constant concentrations; equal blood cell count to artery

Ureter

tube that carries urine (urea dissolved in water) from the kidney to the urinary bladder

Nephron

functional unit of the kidney, dips into the medulla; bowman's capsule + proximal tubule + loop of henle + distal tubule + collectin duct

Ultrafiltration

a high pressure, nonspecific filtration through a the selectively permeable basement membrane, seperating the filtrate from the blood

Filtrate

contains water, amino acids, urea, glucose, small proteins, toxins, drugs, oxygen etc

ADH

antidiuretic hormone, increased levels cause the collecting duct to be more permeable to water, allowing more to be retained in case of dehydration; release by pituitary gland

Hemodialysis

the process by which waste products are filtered directly from the patient's blood using a dialyzer when the kidneys fail

Proximal tubule

80% water reabsorbed by osmosis as well as many other nutrients, ions, minerals; equal concentration to distal tubule

Distial tubule

Follows the loop of Henle; equal concentration to proximal tubule although volume is much lower due to water reabsorbed in the loop of Henle.

Loop of Henle

maintains hypertonic environment in medulla; descending limb impermeable to sodium ions and alows water to exit; ascending limb opposite

Urinary tests

test for blood, glucose, hormones (pregnancy), drugs

Antigen

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

MHC I

found on all body cells with a nucleus; allows immune system to distinguish "self" from "foreign"; not found on blood cells (no nucleus) so blood can be transferred between patients

Specific immunity

specific immunity involves the production of antibodies against a specific antigens by the immune system

Clonal selection

The process by with an specific antigen will activate a specific helper T and B cell, causing the B cell to clone itself many times to produce plasma cells that all produce one type of antibody

Plasma cell

many rough ER and mitochondria to produce lots of antibodies (proteins); short lived cells

Aggulination

clumping caused by antibodies binding to multiple antigens at once

P.A.N.I.C acronym

Precipitation, aggulination, neturalisation (of toxic antigens), inflamation (thorugh histines), complement (system activation)

Passive artificial immunity

injection of monoclonal antibodies like in antivenom

Passive natural immunity

antibodies in breastmilk from mother to baby

Active artificial immunity

vaccination and deliberate exposure to antigen

Active natural immunity

natural exposure to antigen (infection)

Primary immune response

first immune response, generally slow with limited antibodies produced

Secondary immune response

usually much faster, with a large amount of antibodies produced, due to presence of memory B and helper T cells

Exoskeletons

External skeletons that are non-living; cannot "grow" with an organism and must be shed and replaced (e.g shells)

Endoskeletons

Internal skeletons that provide support and framework for muscles and tissue; grow with organism

Antagonistic pairs

Pair of muscles arranged around a joint that produce opposite actions; bicep and tricep in the upper arm produce opposing effects

Grasshopper Leg Muscles

Antagonistic pair of the flexor (pull up, tensing) and extensor (pull out, propelling out) muscle in leg

Synovial joint

A moveable joint in the area where two bones meet; composed of the cartilage, synovial fluid and joint capsule

Joint capsule

seals the joint space and restricts movement to avoid dislocation

Synovial fluid

Fluid in space between bone ends that nourishes cartilage tissue and provides lubrication

Cartilage

Hard tissue that covers the end of bones, providing shock absorption and smoother movement

Skeletal muscle

A muscle that is attached to the bones of the skeleton and provides the force that moves the bones (NOT cardiac or smooth muscle)

Myofibrils

Microscopic protein "myofilaments" that make up muscle fibre cells

Myofilaments

Contractile proteins forming myofibrils; myosin and actin

Sarcomere

Smallest contractile unit of a muscle; a section of a myofibril between two adjacent Z lines

Sacroplasmic reticulum

Specialized endoplasmic reticulum in muscle fibre cells; stores and releases calcium ions used to trigger contraction

Tropomyosin

Rod-like protein found on actin that covers myosin binding sites; also bound to troponin

Troponin

A protein bound to tropomyosin with calcium ion receptors; when calcium ions bind to troponin, it causes tropomyosin to move away from myosin binding sites

Cross bridge formation

Occurs when myosin heads bind to actin at binding sites

Spermatogensis

The production of sperm cells in the seminiflerous tubules of the testes

Oogenesis

The production of egg cells in the ovaries

Spermatogenesis Progression

Spermatogonia > 1 Spermatocytes > 2 Spermatocytes > Spermatid Cells > Spermatozoa

Nurse Cells

Assist differentiation of spermatid cells into spermatozoa, the final form of sperm cells

Semen

A thick fluid containing sperm and other secretions from the male reproductive system

Oogenesis Progression

Oogonia > 1 Oocytes > (meiosis I) 2 Oocytes > (meiosis II) Ovum

Acrosome

A vesicle at the tip of a sperm cell that helps the sperm penetrate the egg, contains enzymes

Acrosome reaction

First step of fertilization, in which sperm binds to zona pellucida and enzymes dissolve the zona

Zona pellucida

A thick, transpartent coating rich in glycoproteins that surrounds an oocyte.

Penetration

Sperm binds to docking proteins on egg; sperm DNA and centrioles enter egg cell

Cortical reaction

cortical granules in egg fuse with plasma membrane; release of enzymes to destory sperm binding sites and prevent polyspermy

Polyspermy

The fertilization of an oocyte by more than one sperm. Prevented in humans through the cortical reaction

Blastocyst implantation

Blastocyst releases digestive enzymes to break down endometrium layer and implant into lining, allowing it to receive nutrients from mother

hCG

human chorionic gonadotropin hormone, secreted by the embyro and stimulates the maintainence of the corpus luteum, which in turn secretes progesterone to maintain thick lining of uterus

Placenta

A structure that allows an embryo to be nourished with the mother's blood supply; chorionic villi from fetus lie in the intervillus space, allowing for exchange of nutrients and waste with mother's blood

Estrogen (Pregnancy)

Stimulate growth of uterine linging, inhibit secretion of FSH and LH

Progesterone (Pregnancy)

Reduce uterine contractions through inhibition of oxytocin, develops breast tissue, maintain endometrium lining; secreted by corpus luteum, then placenta itself

Oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth in a positive feedback loop (more contractions signals release of more oxytocin)

Prostoglandin

Hormone produced by fetus which encourage cervix to dialate and uterine contractions