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HSC biology module 8
Terms in this set (104)
the process of maintaining a constant internal environment by detecting change in stimulus, responding, and using negative feedback loops.
movement away from an ideal state triggers a mechanism to counteract further change and returns the state to normal a change in a variable triggers mechanisms that reverse that change
fast-acting network of nerve cells that transmit impulses between parts of the body and brain in response to internal and external changes
a change in the environment (either external or internal) that is detected by a receptor
a change in the organism resulting from the detection of a stimulus
a sensor that responds to a change in the environment
maintaining the temperature of the body at a near constant level
any part of the body that produces a response to a stimulus. Eg. a muscle contracting to move the arm. a muscle squeezing saliva from the salivary gland. a gland releasing a hormone into the blood.
a specialized cell transmitting nerve impulses; a nerve cell.
are organisms uses internal mechanisms to maintain their core body temperature within a narrow range, despite fluctuations in external environment.
These animals have internal mechanisms allow the generation or production of internal heat energy to regulate their core body temperature. Hence, the term 'warm-blooded' animals.
are organisms that do not have internal mechanisms
These animals DO NOT have internal mechanisms to generate heat and so they must relate on heat from the external environment to regulate their core body temperature. Hence, the term 'cold-blooded' animals.
a physical feature of an organism's body having a specific function that contributes to the survival of the organism
Mountain Pygmy Possum Structural Adaptations
It has short legs,
- round body
- small ears to minimise heat loss.
This is because it will minimise the surface area in which the blood in blood vessel under the skin is exposed to the cold temperature of the environment which will result in heat being carried away convection
Red Kangaroo Structural Adaptations
They have a lot of blood vessels under their forearm and paws. This encourages heat loss via convection to keep their core body temperature within a narrow range, despite the hot ambient surroundings.
changes in an organism's metabolic processes
Mountain Pygmy Possum Physiological Adaptations
During long winters, the possum can enter a state of torpor whereby rate of metabolic activities and core body temperature are reduced to conserve energy. When it is in this state, it is able to tolerate surrounding temperatures of 2 degrees celsius.
- It can also curl into a ball to minimise the surface contact in which it is exposed to the its surroundings in cold conditions.
Red Kangaroo Physiological Adaptations
The muscle glands can also be activated via thermoregulation in kangaroos to generate heat energy in response to cold temperature stimulus detected by thermo receptors on skin and in hypothalamus.
- Panting is performed by Kangaroo whereby heat energy is loss through ventilation. The process of panting allows water on the tongue and mouth surface to be evaporated as the blood under these surfaces are able to be transferred to the cooler water via conduction.
The ways that behaviour is modified for survival
Mountain Pygmy Possum Behavioural Adaptations
- The possums are nocturnal. That is, they sleep during the day and are active during the night to escape the high temperatures of the body to avoid overheating.
- During the day, they can seek shade in holes within rocks or gaps under rocks.
Red Kangaroo Behavioural Adaptations
- Similar to the mountain pygmy possum, the red kangaroos are also nocturnal.
- They also seek shade to avoid overheating during the day.
Internal coordination systems that allow homeostasis to be maintained, including hormones and neural pathways
- Nervous system - neural
- endocrine systems - hormonal
nervous system in maintaining homeostasis
Hypothalamus is the control centre for regulating many internal activities
- Directs effectors to carry out responses through sending messages via neural path ways or chemical messages.
- Conditions that need to be regulated are body temps
- Hypothalamus is the link between ns and endocrine system
Hypothalamus is responsible for
hormone secretions and which helps regulate the internal factors
endocrine system - chemical
Main component are hormones which are chemical messenger secreted by endocrine glands
- Hormones are transported through the blood stream with possess the receptor cells for that specific hormone.
- Hormones help to change activity in cells to maintain homeostasis
Hormones role in internal coordination to achaieve homeostasis
Hormone that stimulates the kidney to retain sodium ions and water
How aldosterone works
-Produced and secreted by the adrenal glands
- receptors receive a drop in blood pressure a message will be sent to secrete the enzyme renin
- renin will then catalyse a reaction to cause the adrenal lands to secrete aldosterone
Nervous system pathway
1. stimulas (heat)
2. receptor converts info into electrical signal
3. transmitted frim receptor to sensory
4. CNS coordinates and sends response
5. passes along motor neurons to relevant effector (muscle) to bring response.
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Mechanisms to maintain water balance in plants
1. reduce internal temperature
2. reduce the exposure of transporting place structure to sunlight
3. Regulating the opening and closing of the stomata
4. water storage
Reducing internal temperature - plants
- leaves covered in waxy material ensures epidermal cells are waterproof, preventing loss of water
- white hairs reflect sunlight which will also reduce the temperature o the surface leaf
reduce the exposure of transporting place structure to sunlight
- Orientation of leaves so that stomata is not exposed to direct sunlight
-Reduction of leaf size
Reduced flower or no petals can reduce the amount of water needed and reduce evaporation
Regulating the opening and closing of the stomata
- Minimise water loss through stomata opening during cooler parts of the day e.g. morning.
some succulents have adaptions such as fleshy stems or leaves that swell up and retain moisture.
the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.
resting potential/ depolarization
- Maintained by active transport
- resting at 70mv
- there is more sodium ions on the outside of the cells, there is more potassium ions inside the cell
resting potential/ depolarization activation
activated by a stimulas make membrane potential more positive.
- sodium volted gates open and sodium ions diffuse across causing depolarization
- Potassium channels open but slower causing depolarization to occur more.
action potential/ repolization
This is restoration of electrical potenial across a plasma membrane.
- approaches max depolarization the volted sodium gates close
- potassium channels are open and continue to diffuse
- increase in . potassium last longer then required.
- Potential become lower than resting value
- after potassium gates close sodium and potassium re-establish resting potential
- genetic diseases
Sickle Cell Anemia
cause genetic disease - Sickle Cell Anemia
effect genetic disease- Sickle Cell Anemia
Incidence Sickle Cell Anemia
prevalence Sickle Cell Anemia
mortality Sickle Cell Anemia
diseases caused by environmental exposure
Melanoma of the skin
environmental exposure cause
Caused by prolonged exposure to UV rays as they penetrate the epidermis of the skin
environmental exposure effect
Causes freckle like spots on skin however they are cancer
Environmental exposure incidence
in 2017 13941 cases and has been increasing
Environmental exposure mortality
Mortality rate will increase with age
increase number of deaths over 1800 in 2017, 1968 has 300
nutritional diseases symptoms
- Sore or bleeding gums
- Fragile capillaries
- Poor wound healing
- Failure of bone to grow or heal properly
nutritional diseases host response
- Vitamin C is essential for healthy growth and development and crucial in various aspects of the immune system, particularly immune cell function
- Vitamin C ensures that the body is able to aid in wound healing, scar formation, repairing cartilage, bone, and teeth, and the ability to absorb iron
nutritional diseases treatment
If insufficient vitamin C is consumed in the daily daily, vitamin C tablets can be used as substitute.
nutritional diseases incidence/ prevalence
prevalent in developing countries where access to vitamin C rich foods is not always accessible, as well as areas struggling with malnutrition. There have been outbreaks of scurvy in refugee camps, with Globalisation, Migration and Health: Challenges and Opportunities (2016) reporting a prevalence of 5 to 45%.
nutritional diseases mortality
The mortality rate of scurvy has since decreased and is considered to be an easily treatable disease. Within 24 hours, patients can expect to see improvement in fatigue, lethargy and pain. Bruising, bleeding and weakness start to resolve within 1 to 2 weeks. Long-term effects are not always likely, except in the case of severe dental damage.
Lung cancer is the uncontrolled growth of abnormal cells in one or both lungs, usually in the cells lining air passages.
Passive smoking (secondhand smoke)
Exposure to asbestos fibers
Exposure to radon gas
Exposure to diesel exhaust
cancer host response
ow antigenicity and heterogeneous phenotype lung cancer evades host immune defense. The cytotoxic anticancer effect is suppressed by a complex mechanism in tumor microenvironment. The population of regulatory T cells (Tregs) plays a crucial role in this inhibition of immune response.
Or a combination of these
- higher incidence in men rather than women
- As awareness was created incidence has begun to decrease
30 deaths per 100,000 persons with lung cancer
13,092 diagnosed, 9,173 deaths
What is epidemiology?
study of the cause, distribution and frequency of a disease in specific population in order to establish measures to prevent the disease
Types if epidemiology
The aspect of epidemiology concerned with organizing and summarizing health-related data according to time, place, and person
a form of epidemiology that investigates causes and associations between factors or events and health.
- Morbidity and mortality
- Starts to develop a hypothesis
begins with a hypothesis about a particular disease; experiments to test the hypothesis are then conducted with a group of people
- used to test the effectiveness of a new drug
prevention of a non-infectious disease
educational programs and campaigns
educational programs and campaigns
Function of the kidney
1. removal of urea which is the break down amino acids into ammonia
2. Osmoregulation - the control of water balance
What is the kidney
It is the bodies filtration system. Blood is filtered out at the glomerulus, collected by the bowmans casual and then reabsorbed into the capillaries in the loop of henele. Waste products are not reabsorbed.
a high pressure filtration through a semi-permeable membrane in which colloidal particles are retained, while the small sized solutes and the solvent are forced to move across the membrane by hydrostatic pressure forces.
The absorption of certain selected molecules back into the blood from the fluid in the nephron tubule. This is typically glucose and amino acids.
Loop of Henle
the part of a kidney tubule that forms a long loop in the medulla of the kidney, from which water and salts are resorbed into the blood.
There is an descending loop which is permeable to water and a descending loop which ic permeable to na+
If you are controlling your water balance you are
controlling your blood pressure which means you are controlling your blood volume and maintaining homeostasis
regulation of solute concentrations and water balance by a cell or organism using ADH.
Kidney disease - causes
- Kindey stone + tumor
an artificial method of filtration to remove excess waste materials and water from the body/an artificial method of filtration to remove excess waste materials and water directly from the blood
Steps of hemodialysis
1. a fistula needs to be created, this connects an artery to a vein in the arm.
2. Blood from the vein in pumped through a semipermeable membrane that allows wast molecules to pass through
3. The tube passes through dialysis fluid which creates a concentration gradient
4. filtered blood is returned to the body through he artery.
decreased ability to perceive sounds compared to what the individual or examiner would regard as normal
Sensorineural Causes of hearing loss
Caused by damage to the delicate structures of the inner ear and/or its associated nerves
. It can be caused by:
• exposure to loud noise.
• damage to the haie cells in the organ int he corti.
Conductive hearing loss
Caused by mechanical disruption to the middle ear.
It can be caused by:
• middle-ear infection.
• perforated eardrum.
• damage to the middle ear bones.
• a benign growth in the middle ear.
Technology to assist with hearing loss:
Bone conduction implants
What is a cochlear implant?
Cochlear implants compensate for damaged or non-working parts of the inner ear.
Enable people to detect very soft speech and environmental soundsCochlear implants are electronic devices that are used to give hearing to those who are profoundly deaf. There are two parts. The outer part contains a microphone, while the inner part (the implant) includes an electrode that feeds into the cochlea and directly stimulates the hearing nerves.
how to cochlea implants work
Microphone in the ear picks up the sound and sends them to a microprocessor which converts them into electrical signals. These are sent to a transmitter, then a receiver implanted beneath the skin of the skill. Signals are send to the cocchlea where they stimulate auditory nerve endings
Bone conduction implants
Bone conduction implants are used to improve hearing for those who have conductive hearing loss. They transmit vibrations through bone to the inner ear, bypassing the defective outer and middle ear.
how do bone conduction implants work
The processer picks up sound signals and turns them into vibrations that are sent through the bone to the implant which in turn directly vibrates the hone and the vibrations in the inner ear.
Traditional hearing aids come in many different shapes and sizes and are fitted to a patient by an audiologist depending on the type and severity of the patient's hearing loss. Typically, hearing aids help a person to hear by making sounds louder as they enter the outer ear.
How do hearing aids work
Using a microphone to convert sound energy to electrical energy, an amplifier amplifies electrical energy, earphone converts amplified electrical energy back into sound energy of greater intensity.
Functions of the eye
1. receives light stimuli
2. turns stimuli into nerve impulses
3. optic nerves transmits nerve impulses to the brain
4. brain decodes and interprets nerve impulses into images
Short sightedness (myopia) is caused when light is focussed at a point that falls short of the retina.
Long sightedness (hyperopia) is caused when light is focussed at a point beyond the retina. These vision problems can result from a defect in either the lens or the shape of the eye, or both.
An astigmatism is a common eye disorder that results from a cornea which is not spherical. As a result, light is not focussed on the retina the same all planes
A cataract is a defect in the eye, characterised by opacity (or translucency) of the lens
Glaucoma is a common eye disease caused by a build up of pressure in the eye, which damages the optic nerve and the blood vessels that carry blood to the retina. In turn this is usually caused by a blockage in the drainage channel that drains fluid from the aqueous humour.
A detached retina occurs when the retina begins to separate from the sclera which contains the blood vessels that provide necessary oxygen and nutrients. The first sign of retinal detachment is often 'floaters', sudden flashes of light or shadows in the field of vision
Macular degeneration is an eye disease in which the retina begins to degrade, which results in a loss of sharpness in vision.
Technology to assist with eye sight
Laser eye surgery
Corrective lenses Spectacles and contact lenses
correct the vision of people with hyperopia, myopia and/or astigmatism, by refracting the light entering the eye in a way that is complementary to the defect in the eye
laser vision correction
In laser vision correction, a small circular flap is created in the cornea using a precise metal blade or a laser that creates series of tiny closely positioned bubbles in the cornea. The flap is then folded back to reveal a layer of the cornea called the stroma. A laser is then used to vaporise material in the corneal stroma, in order to reshape the cornea, to correct for the refractive error in the eye. Finally the flap is replaced and the eye allowed to heal.
number of people contracting a disease during a time period
the total number of cases suffering from a disorder
the number of deaths per thousand
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