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Biology Grade 12 Final Exam
Terms in this set (93)
Homeostasis (Chapter 8)
the tendency of the body to maintain a relatively constant internal environment (Comfortable Balance)
Feedback Systems (8.1)
Body's method of maintaining homeostasis
Positive Feedback (8.1)
Response will increase or strengthen the change in the variable. Eg. During delivery oxytocin causes more contractions which releases more oxytocin.
Negative Feedback (8.1)
The response reverses the change in the variable. Eg. Cold -> Shiver = Warmth
The Scout. Monitors and detects changes in internal environment. In the body. Notices cold - doesnt know what to do about it
Control Centre (8.1)
Boss, communicator. Knows the optimal level or range of values of a variable needed to achieve homeostasis. Tells effectors to issue a response. Receives notice of internal temperature decreasing - tells effectors to respond.
Thugs, Dealer - receives signals from control centre. Issues proper response. Learns of cold - tells body to shiver.
Nervous System (8.2)
The bodily system that transmits signals to produce actions. E.g. Brain tells arm to move Divided into Central and Peripheral
Central Nervous System (CNS) (8.2)
Brain and Spinal Cord. integrates and processes information sent by nerves. Brain sends signal down spinal cord - goes down efferent neurons, produces function
Peripheral Nervous System (PNS) (8.2)
Everything else other than brain and spinal cord. Divided into somatic and autonomic.
Somatic Nervous System (SNS) (8.2)
Under Voluntary control. E.g. Moving arm
Autonomic Nervous System (ANS) (8.2)
Not under conscious control. Autonomic = Automatic = Involuntary. E.g. Heart Beating
Basic structural unit of nervous system. Equivalent of a cell. Used to pass information. Supported by glial cells.
Individual neurons grouped together with a common function
Neuron Composition (8.2)
Dendrite - tree branches - receives signal, sends down axon
Axon - long part - conducts electrical signal - Myelin Sheath - insulating layer surrounding axon. Speeds up rate of impulse transmission. Composed of Schwann cells (type of glial cell)
Node of Ranvier - Gap between Schwann cells
Cell Body - nucleus and such
Branching ends of axon - roots - Terminal branch - pass signal to other neurons
Bipolar Neuron (8.2)
Coming of two ends
Single Main Dendrite
Found in smelling region (olfactory region) of the brain and (ear, eye, nose)
Unipolar Neuron (8.2)
Only one extension of cell body everything one
Dendrite and axon are fused
Found in peripheral nervous system
Multipolar Neuron (8.2)
Like a tree - Multi branches
Found in Brain and Spinal Cord
Sensory Neuron (8.2)
The link between sensory and motor. Found in central nervous system
Motor neuron (8.2)
Neuron that performs action. Direct connection to effectors.
Reflex Arc (8.2)
simple connection of neurons that results in reflex action.
E.g. touching something hot -> hand pulls away
Splits impulse in interneuron, one to brain, one to motor neuron.
Resting Membrane Potential (8.2)
Inside of cell is negatively charged
Sodium Potassium Pump (8.2)
Potassium enters cell to depolarize membrane (brings towards positive charge)
At +40 mV. Potassium channels open and Potassium exits (hyperpolarization, brings towards negative charge)
Goes back to resting membrane potential
Figure 8.14 pg 357
Action Potential (8.2)
The movement of an electrical impulse across and axon. All or none principle - Threshold is either reached or not reached - either fires 100% or not at all.
Nodes of Ranvier (8.2)
exposed areas of axon in between schwann cells. Spots where Sodium enters. where neuron gets strength to keep going. Makes sure that action potential only travels forward. Depolarizes one section at a time.
Junction between two neurons or neuron and effector (neuromuscular junction).
Synaptic Transmission (8.2)
Impulse travels to synaptic terminal.
causes synaptic vesicles containing neurotransmitters to move toward and fuse with presynaptic membrane
Neurotransmitters are released into synaptic cleft.
Neurotransmitters bind to receptor proteins, ion channels open (sodium potassium pumps), causing action potential in next cell. on postsynaptic neuron and have whatever effect necessary. Figure 8.16 pg 359
Neuromuscular Junction (8.2)
Same process as synaptic transmission. Except neurotransmitter is Acetlycholine- which causes contraction of the muscle.
Central Nervous System (CNS) (8.3)
Two Different types of matter in the CNS. Grey and white.
White is myelinated axons - Fatty sheath (Steak)
Grey is cell bodies, dendrites and unmyelinated axons
Spinal Cord Structure (8.3)
Butterfly = grey matter
outside = white matter
Three layers of tough elastic tissue within skull and spinal column that directly enclose brain and spinal cord
Peanut in red skin and shell
Divided into three sections.
The Hindbrain - cerebellum, medulla oblongata, pons
The Midbrain - Midbrain
The Forebrain - Thalamus, hypothalamus, cerebrum
Unconscious coordination and balance of reflexes and posture as well as fine voluntary motor skills
Medulla Oblongata (8.3)
connects brain and spinal cord (brain stem)
coordinates reflexes, and automatic bodily functions that maintain homeostasis. i.e. heart rate
serves as a relay between neurons of the two halves of the cerebrum, the cerebellum and the rest of the brain
relays sensory information between the hindbrain and the forebrain.
Main relay centre of the brain. All sensory information relays through thalamus before arriving at cerebrum.
Helps to regulate body's internal environment and emotion. (Control Centre) Gives signal for response. Link between nervous and endocrine system
Largest part of brain. Divided into left and right hemisphere. Learning, memory... intellectual functions. Interprets sensory information and sends response.
The Blood-Brain Barrier (8.3)
The meninges create barrier between CNS and blood. so that blood does not enter directly into brain and spinal cord.
Cerebrospinal Fluid (8.3)
The fluid that occupies the empty space in your empty spinal cord.
Cerebral Cortex (8.3)
Thin outer covering of grey matter that covers each hemisphere of the brain
Corpus Callosum (8.3)
The joining of the two hemispheres of the cerebrum. Allows them to communicate.
Occipital Lobe (8.3)
Back of the brain. Receives and analyzes visual information.
Temporal Lobe (8.3)
Along the side of the brain. Main function is auditory reception. Understanding speech. Retrieving visual and verbal memories.
Parietal Lobe (8.3)
Middle part. Receives and processes sensory information from the skin. Touch. Helps process information about the body's position .
Frontal Lobe (8.3)
The largest part, right at the front. Controls reasoning, critical thinking, memory and personality. As well as voluntary motor movement.
Sympathetic nervous system (8.4)
Within Autonomic. Automatic responses. Increases involuntary functions via norepinephrine. E.g. heart rate increase
Parasympathetic nervous system (8.4)
Within Autonomic. Automatic responses. Decreases involuntary functions. E.g. heart rate decrease
Endocrine System (9.1)
Endocrine system affects body and maintains homeostasis via hormonal response. (Releases hormones) made up of glands and hormones
Endocrine Glands (9.1)
Glands that secrete chemical messengers called hormones.
Hormone Action on Target Cells (9.1)
hormone finds target cell and binds to specific receptor. This causes a reaction within the cell. E.g. hGH attaches to muscle cell, makes muscle grow.
Steroid Hormones (9.1)
Lipid Soluble. Go through cell membrane (phospholipid bilayer easily) Once in cell bind to specific receptor, affect genes and the synthesis of a specific protein/ mRNA molecule.
Water Soluble Hormones (9.1)
Cannot go through membrane by themselves. Bind to specific receptor protein in membrane. Leads to activation of an enzyme that changes ATP to cAMP. cAMP activates an enzyme cascade, causing certain reaction to happen. e.g. glycogen is broken down into glucose.
Tropic Hormone (9.1)
hormone that targets endocrine glands and stimulate to release other hormones.
Posterior Pituitary (9.2)
Does not produce hormones. Stores and releases ADH and Oxytocin.
Anterior Pituitary (9.2)
Synthesizes and releases hormones (TSH, ACTH, PRL, hGH, FSH, LH).
Stimulates liver to secrete growth factors. See Chart for other functions
Thyroxine (T4) (9.2)
TSH causes release of T4. See chart for other functions
Hypothyroidism -> when thyroid does not release enough thyroxine, causes obesity
Hyperthyroidism -> Overproduction of T4
tropic hormone that stimulates thyroid to produce T4
Adrenal Gland (9.2)
Located on top of kidneys. divided into adrenal medulla (Short term stress response) and adrenal cortex (Long term stress response).
Adrenal Medulla (9.2)
produces epinephrine and norepinephrine, which when under stress, induces fight or flight response, stimulating sympathetic nervous system, increases rates.
Adrenal Cortex (9.2)
ACTH is the tropic hormone for it. causes release of cortisol (Glucocorticoid) from adrenal cortex. Also releases aldosterone (mineralcorticoid) -> raises blood pressure by reabsorbing sodium.
Made up of Beta cells and Alpha cells. Beta cells release insulin, and alpha cells release glucagon. Insulin is released after eating (Stores glucose -> decreasing blood glucose). Glucagon is released when hungry (takes from storage -> increases blood glucose).
Islets of Langerhans (9.3)
Clusters of beta and alpha cells found throughout the pancreas
Diabetes Mellitus (9.3)
pancreas doesnt produce enough insulin or body doesnt respond to insulin. constant state of high blood sugar (hyperglycemia). Bad for cells, cells starve. as a result body switches to using protein and fat as energy.
Type 1 Diabetes (9.3)
Juvenile Diabetes -> insulin dependent. Immune system produces antibodies that destroy beta cells of pancreas.
Type 2 Diabetes (9.3)
Insulin receptors on cells stop responding to insulin or beta cells just stop/slow down insulin production over time.
Organ that produce reproductive cells. (Ovary -> Egg, Testicle -> Sperm) and sex hormones
Sex hormones male (9.4)
GnRH is the tropic hormone, comes from hypothalamus. Puberty starts when hypothalamus releases more of GnRH. GnRH acts on anterior pituitary causing it to release LH and FSH.
FSH causes testicles to release inhibin which acts on anterior pituitary to inhibit release of FSH.
causes testes to release testosterone. Testosterone acts as negative feedback to inhibit the release of LH in the pituitary.
Sex hormones female (9.4)
Estrogen -> female testosterone, maintains secondary sex characteristics of women and progesterone. FSH and LH cause release of both.
Hormone Replacement Therapy (9.4)
Not enough hormones, use synthetic replacement hormones.
Excretory System (10.1)
The system that regulates the volume and composition of body fluids by excreting metabolic wastes and recycling some substances for reuse.
Functions of Excretory System (10.1)
Excretes metabolic wastes - urine
Maintains water/salt balance - by absorbing water or salts through hormones.
Maintains acid base balance - balancing pH of blood
Secretion of Hormones - Kidneys secrete calcitriol and erythropoietin
produce urine, contain nephron.
transports urine from kidney to bladder.
Renal Artery (10.1)
Main artery that provides blood for the kidney
Renal Vein (10.1)
Carries blood away from kidney.
microscopic tube like filtration unit in the kidneys. Filters and reabsorbs various substances from the blood, and produces urine. intertwined with capillaries, exchange blood.
Bowman's capsule (10.1)
At the top of each nephron is a cap like formation called the bowman's capsule. filters what goes into glomerulus of nephron
Collection of capillaries in nephron, surrounded by bowman's capsule.
connected to bowman's capsule and loop of Henle. from loop of henle goes to collecting duct
Collecting Duct (10.1)
water conservation device that reclaims water from filtrate passing through it. Makes sure we dont lose too much water through urine.
Urine Formation (10.2)
Glomerular Filtration - Moves water and solutes from the blood to the nephron. (called filtrate)
Tubular Reabsorption - removes useful substances from filtrate and returns back to blood.
Tubular Secretion - Moves additional waste and excess substances from the blood into the filtrate.
Water Reabsorption - Removes water from the filtrate and back the blood
Refer to 10.6
Loop of Henle (10.2)
Section of nephron between proximal and distal tubule. main function is reabsorption of water and ions.
Refer to 10.8
Increases permeability of distal tube and collecting duct in the nephron, allowing more water to be reabsorbed into the blood from the filtrate. Depends on how much water there is in body. Thirsty = more ADH released by pituitary gland
Reabsorption of Salts (10.3)
Aldosterone is released by adrenal cortex. Increases reabsorption of sodium. When sodium is reabsorbed into blood water will follow, conserving water.
Renal insufficiency - Kidneys cannot maintain homeostasis due to damage in the nephrons. can be caused by diabetes mellitus.
Removes wastes and excess fluid when your kidney cant because of renal failure.
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