Term 3 Flashcards
Define Homeostasis
The maintenance of an internal environment within a living organism despite. Internal or external changes to the environment.
Negative Feedback Loop
Stimulus, regulator, effects, response/communication
Negative Feedback
Some variables triggers a counteractive response, in order to come back to some set points.
Positive Feedback
Instead of getting a counteractive response to some variable, you’re instead intensify the variable.
Chemoreceptor
Chemical
Photoreceptor
Light
Mechanoreceptor
Touch, Pressure, Stretching, Motion, Sandwaves
Thermoreceptor
Heat
Nociceptor
Detects damage
How is Homeostasis Maintained?
Hormonal homeostasis pathways….
… involve the endocrine system, can be slow, chemical messengers, travelling in bloodstream
Natural Homeostasis Pathways
Involves the nervous system, is very rapid, Electric impulse, travelling along the nerves.
What is Hormonal Control?
Hormones are chemical messages produced by an organism to regulate the activity of cells and organs.
Endocrine-Travel long distances through the body to target cells.
The Endocrine System; in mammals
In mammals, hormonal are produced in the endocrine glands which are released directly into the blood vessels.
What systems work together to maintain homeostasis?
Endocrine and Nervous system
What does Hormones affect?
Hormones affects only certain tissue cell or organs called Target Organs.
Target Cells Must Have…. and why do they bind?
They must have protein receptors present on the cell membrane to allow the hormone to attach. Hormones must bind to the target cell to influence the cell.
The Flow of Information along Nervous System (3)
- Receptor detects a change in conditions (Stimulus)
- Receptor to the CNS by a sensory memory (message)
- CNS to an organ an (effector) carries out a response a motor Nevron carries the message.
What does CNS stand for?
Central Nervous System
What does PNS mean?
Peripheral Nervous System
Moto Nevron
Carry messages from the brain to allow us to move our muscles
Interneuron
Connect neuron to other neuron
Sensory Neuron
Sensory neuron receive information from sense organs. Send sensory information to our brain and spinal cord.
What is Thermoregulation
Thermoregulation is maintenance of a constant internal temperature of an organism independent of the temperature of the environment.
Thermoregulation-What happens when the temperature approaches 10 degrees
As the temperature approaches 10 degrees enzymes activity shows when it is below this temperature
Thermoregulation- What happens when the temperature is above 45 degrees?
Above 45 degrees enzymes start to denature, stopping metabolic activity.
Where does Ectotherms get their body heat
They get their body heat mainly from their environment and can tolerate a reasonably wide range of body temperatures.
What are Endotherms?
They are animals that can maintain a constant body temperature independent of the environment.
Thermoregulatory Mechanisms:
- Physiological Mechanisms
- Thermogenesis=
Is the production of heat within tissues to rise body temperatures.
Thermoregulatory Mechanisms:
1. Physiological Mechanisms
Vasodilation=
Dilation of blood vessels in the skin
Thermoregulatory Mechanisms:
1. Physiological Mechanisms
Vasoconstriction=
Construction of blood vessels in the skin
Thermoregulatory Mechanisms:
1. Physiological Mechanisms
Evaporative heat loss
An arrangement of blood vessel in which heat flows from warmer to cooler blood usually reducing heat loss.
Behavioural response:
kleptothermy
is any form of thermoregulation by which an animals steals the body heat of another animal
Behavioural response:
Torpor:
Physical or mental inactivity in which the metabolic rate is lowered
Behavioural response:
Hibernation
Is used to survive in winter
Behavioural response:
Aestivation
Is used to survive summers
Homeostatic Mechanism:
Thyroid hormones
Thyroid hormones increase metabolic rate
Homeostatic Mechanism:
Insulin
Insulins rule in the thermoregulation is to activate genes that control body temperatures
Structure Features:
Brown adipose tissues
Specialised for rapid heat production. Transfer energy from food into heat.
Structure Features:
Increased number of mitochondria per cell
Enable organism to generate heat by increasing the rate at which they metabolise fats and sugar.
Structure Features:
Insulations
Traps warm air to insulate organism
e.g, features, blubber
What is difference between an infectious and non-infectious disease?
Infectious disease can spread, non-infectious cannot
What are the two types of parasites?
Endo and Ecto
Give three examples of non-infectious diseases
diabetes, obesity, cancer
Which lines of defence are classed as the innate immune system?
1st and 2nd
What is the role of the first line of defence?
To provide physical and chemical Barries to prevent the entry of pathogens
What two processes are involved in the second line of defence?
Inflammation and Phagocytosis
Which line of defence do cilia and mucus membrances
1st line
list the 4 virulence factors that aid in pathogenesis
Adherence factors, invasion factors, capsules and toxins
Epidemics
A widespread occurrence of a disease in a community at a particular time
Pandemics
A disease that affects a whole country or the entire world (more to do with geographical spread of disease)
Proportion of population that is immune or has been immuised herd immunity
Occurs when a large percentage of the populations is immunised against a disease to protect those people in a population who are especially vulnerable to infectious diseases
