Communication, homeostasis and energy (Module 5) Flashcards
Cell signalling
the way in which cells communicate with each other
Effector
Cell, tissue or organ that brings about a response
Homeostasis
Maintaining a constant internal environment despite changes in external and internal factors
Negative feedback
The mechanism that reverses a change, bringing the system back to the optimum
Positive feedback
The mechanism that increases a change, taking the system further away from the optimum
Sensory receptors
Cells/sensory nerve endings that respond to a stimulus in the internal or external environment of an organism and can create action potentials
Ectotherm
Organism that relies on external sources of heat to maintain body temperature
Endotherm
Organism that uses heat from metabolic reactions to maintain body temperature
Hypothalamus
Part of the brain that coordinates homeostatic responses
Excretion
Removal of metabolic waste from the body
Metabolic waste
A substance that is produced in excess by the metabolic processes in the cells, it may become toxic
Hepatic artery
Oxygenated blood from the heart - aorta - hepatic artery - liver
Hepatic portal vein
Deoxygenated blood from digestive system enters liver via hepatic portal vein
Hepatocytes
Liver cells
Sinusoid
Chamber where blood from the hepatic portal vein and hepatic artery mix in order for cells to remove useful substances
Kupffer cells
Found in sinusoids
Breakdown and recycle old red blood cells
Hepatic vein
Deoxygenated blood from liver to vena cava
Bile canaliculus
Thin tube that collects bile secreted by hepatocytes
Ornithine cycle
series of biochemical reactions that convert ammonia to urea
Nephron
functional unit of the kidney
Ultrafiltration
Filtration of the blood at a molecular level under pressure
Antidiuretic hormone (ADH)
Hormone that controls the permeability of the collecting duct walls
Osmoreceptor
Sensory receptor that detects changes in water potential
Glomerular filtration rate (GFR)
Rate at which fluid enters the nephrons
Monoclonal antibodies
Antibodies made from one type of cell - they are specific to one complementary molecule
Renal dialysis
A mechanism used to artificially regulate the concentrations of solutes in the blood
Pacinian corpuscle
Pressure sensor in skin
Sensory receptor
Cells/sensory nerve endings that respond to a stimulus in the internal or external environment of an organism and can create action potentials
Transducer
A cell that converts one form of energy into another - in this case to an electrical impulse
Motor neurones
Neurones that carry an action potential from the CNS to the effector
Myelinated neurone
Has an individual layer of myelin around it
Non-melinated neurone
No individual layer of myelin
Relay neurones
Join sensory neurone to motor neurones
Sensory neurones
Neurones that carry an action potential from the sensory receptor to the CNS
Action potential
A brief reversal of the potential across the membrane of a neurone causing a peak of 40+mV compared to the resting potential of -60mV
Resting potential
The potential difference across the membrane while the neurone is at rest
Cholinergic synapse
Synapse that uses acetylcholine as its neurotransmitter
Neurotransmitter
Chemical used as a signalling molecule between two neurones in a synapse
Summation
Occurs when the effects of several excitatory post-synaptic potentials (EPSPs) are added together
Endocrine system
Communication system using hormones as a signalling molecule
Hormones
Molecules released by endocrine glands directly into the blood
Ast as messengers carrying signals to specific target organs/tissues
Target cells
Cells that have a specific receptor on their plasma membrane that is a complementary shape to the shape of the hormone molecule
Adrenal cortex
Outer layer of the adrenal gland
Releases cortisol
Adrenal gland
Pari of glands above the kidneys
Adrenal Medulla
Inner layer of adrenal gland
Releases adrenaline
Adrenaline
Hormone released from the adrenal glands, which stimulate the body to prepare for fight or flight
Beta cells
Found in Islets of Langerhans
Secrete insulin hormone
Glucagon
Hormone that causes increase in blood glucose concentration
Glycolysis
Gluconeogenesis
Insulin
Hormone released from beta cells in pancreas
Cause decrease of blood glucose levels
Glycogenesis
Alpha cells
Found in Islets of Langerhans
Secrete glucagon hormone
Hypoglycaemia
Blood glucose concentrations drop below 4mmol dm3- for long periods of time
Hyperglycaemia
Blood glucose concentrations too high for long periods of time
Diabetes mellitus
Condition where blood glucose concentrations can not be controlled effectively
Stem cells
Unspecialised cells that have the potential to develop into any type of cell
Abiotic components
Components of an ecosystem that are nonliving
Alkaloids
Organic nitrogen-containing bases that have important physiological effects on animals
.nicotine
.morphine
.quinine
Biotic components
Components of an ecosystem that are living
Pheromone
Any chemical substance released by one living things which influences the behaviour or physiology of another living thing
Tannins
Phenolic compounds located in cell vacuoles or in surface wax on plants
Tropism
Directional growth response in which the direction of the response is determined by the direction of the external stimulus
Apical dominance
Inhibition of lateral buds further down the shoot by chemicals produced by the apical bud at the tip of the plant shoot
Auxins
Plant hormones which are responsible for regulating plant growth
Gibberellins
Plant hormones which are responsible for the control of the stem elongation and seed germination
Geotropism
Directional growth response to gravity
Phototropism
Directional growth response to light
Autonomic nervous system
part of the nervous system responsible for controlling the involuntary motor activities of the body
Central nervous system
Brain
Spinal cord
Peripheral nervous system
Sensory and motor nerves connecting the sensory receptors and effectors to the CNS
Somatic nervous system
Motor neurones under conscious control
Cerebellum
Region of the brain coordinating balance and fine control of movement
Cerebrum
Region of the brain dealing with higher functions such as conscious though
Divided into two cerebral hemispheres
Hypothalamus
Part of the brain that coordinates homeostatic responses
Medulla oblongata
Region of the brain that coordinates homeostatic responses
Pituitary gland
. Endocrine gland at base of brain
. Anterior lobe secretes many hormones
. Posterior lobe stores and releases hormones mode in the hypothalamus
Knee jerk reflex
Reflex action which straightens the leg when the tendon below the knew cap is trapped
Reflex action
Response that does not involve processing by the brain
Adenyl cyclase
Intracellular enzyme which is activated by certain hormones
Cyclic AMP (cAMP)
Secondary messenger released inside cells to activate a response
Cardiac muscle
Muscle found in the heart wall
Involuntary muscle
Smooth muscle that contracts without conscious control
Neuromuscular junction
Structure at which a nerve meets the muscle
Similar in action to a synapse
Skeletal muscle (striated)
Muscle under voluntary control
Creatine phosphate
A compound in muscle that acts as a store of phosphates and can supple phosphates to make ATP rapidly
Granum (grana pl)
Inner part of chloroplasts made of stacks of thylakoid membranes where the light dependent stage of photosynthesis is takes place
Photosynthetic pigment
Pigment that absorbs specific wavelengths of light and traps the energy associated with the light
. Chlorophyll a and b
. Carotene
. Xanthophyll
Photosystem
System of photosynthetic pigments found in thylakoids of chloroplasts
. Traps protons and passes energy to primary pigment (Chlorophyll a)
. During light-dependent stage
Stroma
Fluid filled matrix of chloroplasts where light-independant of photosynthesis takes place
Thylakoid
Flattened membrane bound sac found inside chloroplasts
contain photosynthetic pigments
Site of light-dependant stage
Electron carriers
. Molecules that accept one or more electrons and donate them to another carrier
. Proteins embedded in thylakoid membranes
. Form electron transport chain
. NAD and NADP are electron carriers
NADP
Nicotinamide adenine dinucleotide phosphate
Coenzyme and electron and hydrogen carrier
Photophosphorylation
Generation of ATP from ADP and inorganic phosphate in the presence of light
GP
intermediate compound in Calvin Cycle
RuBP
. Five-carbon compound present in chloroplasts
. Carbon dioxide acceptor
TP
. Three-carbon compound
. Product of the calvin cycle
. Used to make other larger organic molecules
Water stress
Condition experienced by a plant when water supply becomes limiting
Glycolysis
First stage of respiration
10 stage metabolic pathway
Glucose converted to pyruvate
Cristae
Inner highly folded mitochondrial membrane
Mitochondrial matrix
Fluid filled inner part of mitochondria
Decarboxylation
Removal of carboxyl group from substrate molecule
Dehydrogenase
Removal of hydrogen atoms from a substrate molecule
Substrate-level phosphorylation
Production of ATP from ADP and Pi during glycolysis and the krebs cycle
Chemiosmosis
Flow of protons down concentration gradient across a membrane through a channel associated with ATP synthase
Oxidative phosphorylation
Formation of ATP using energy released in electron transport chain and in the presence of oxygen
Last stage in aerobic respiration
Respiratory substrate
Organic substrate that can be oxidised by respiration
Energy release to make ATP molecules
Spatial summation
signals from multiple stimuli coordinated into single response
Temporal summation
2 or more nerve impulses arrive in quick succession from same presynaptic neurone.
makes action potentials more likely as more neurotransmitter released.
