Coordination and response Flashcards
Where do flowering plants grow?
In specific areas called meristems
Examples of meristems include roots, shoots, and buds.
What are the four main organs of a flowering plant?
- Flower
- Leaf
- Stem
- Roots
Each organ has a specific function related to the plant’s growth and reproduction.
What is the primary function of the flower in flowering plants?
Attracts pollinators for sexual reproduction
What is the role of leaves in flowering plants?
Photosynthesis
What is the function of the stem in a plant?
Supports the plant and contains transport systems
What do roots do for the plant?
Anchors the plant in ground and takes up mineral ions and water
What factors do plants grow to maximize availability of?
- Light
- Water
- Carbon dioxide
What is a tropism?
A directional growth response towards or away from a stimulus
What is a positive tropism?
Growth towards the stimulus
What is a negative tropism?
Growth away from the stimulus
What is phototropism?
A response to light
What is geotropism?
A response to gravity
In phototropism, which part of the plant shows a positive response?
The shoots
In phototropism, which part of the plant shows a negative response?
The roots
What hormone is responsible for the growth responses in plants?
Auxin
How does auxin travel through the plant?
Dissolved in water
What effect does auxin have on shoot growth?
Promotes growth
What effect does auxin have on root growth?
Inhibits growth
What causes the movement of the plant in response to light?
Cell elongation on one side of the shoot/root
How does auxin affect the shoot in response to light?
It accumulates on the shady side, causing those cells to elongate
What advantage does the shoot gaining more light provide?
More light for photosynthesis
What happens to auxin in the root when exposed to sunlight?
It gathers on the lower side
What is the result of auxin accumulation in the root?
More growth on the side with less auxin
What advantage does the root growing down into the soil provide?
Anchors the plant and finds water and mineral ions
What is the effect of placing cress seeds in bright light?
They grow straight, short, and with green leaves due to even auxin distribution
Bright light encourages leaf formation and chlorophyll production.
What happens to cress seeds in complete darkness?
They develop long, spindly stems with pale yellow leaves as they use energy to grow upwards instead of producing chlorophyll
Auxin is evenly distributed, so the shoot grows straight up.
What is the outcome when cress seeds are placed in a box with one hole letting in light?
There is growth towards the light with pale green leaves
Auxin accumulates on the shaded side, causing elongation and bending towards the light.
What is the role of mica in investigating phototropism?
Mica is impermeable, preventing auxin diffusion and resulting in no response to light
This shows the importance of auxin movement in plant growth.
What happens when gelatin is used in the investigation of phototropism?
Auxin diffuses through gelatin, leading to cell elongation and bending towards the light
Gelatin’s permeability allows auxin to move down the shoot.
What occurs when the tip of the shoot is removed and placed on one side?
Auxin diffuses down one side only, causing cell elongation and bending towards the light
This demonstrates how auxin distribution affects plant directionality.
How does auxin behave when collected in an agar jelly block?
It diffuses out and accumulates on one side, causing cell elongation and bending
This experiment illustrates auxin’s role in directional growth.
What is geotropism?
The response of the plant to the stimulus of gravity.
How do shoots respond to gravity?
Shoots are negatively geotropic, growing away from gravity
More auxin accumulates on the lower side when a shoot is horizontal, causing it to bend upwards.
What is the behavior of roots in response to gravity?
Roots are positively geotropic, growing towards gravity
Auxin on the lower side inhibits growth, causing the upper side to grow faster and bend downwards.
Why is geotropism important for plants?
It allows roots to anchor plants and gain more water and minerals.
What is the function of the skin?
The skin serves several functions:
* Tough outer layer which resists mechanical damage.
* Barrier to the entry of pathogens.
* Impermeable, preventing water loss.
* Senses touch and temperature changes.
* Controls heat loss.
What happens when the body temperature is too high?
When the body temperature is too high:
* We sweat.
* Hairs lie flat.
* Vasodilation occurs.
What happens when the core temperature is too low?
When the core temperature is too low:
* No sweating.
* Hairs become erect due to erector muscles.
* Vasoconstriction occurs.
* Shivering happens.
* The liver increases its metabolism.
What is the role of sweat in temperature regulation?
Sweat helps to cool the body by evaporating from the skin surface, balancing the water loss from fluids taken in from food and drink.
Which receptors are located in the dermis?
Touch and pressure receptors are located in the dermis.
What type of muscle is involved in hair erection?
Hair erector muscle.
What is the primary component of fatty tissue?
Fatty tissue is made from adipocytes.
What is vasodilation?
Vasodilation is the widening of blood vessels to increase blood flow and heat loss.
What is vasoconstriction?
Vasoconstriction is the narrowing of blood vessels to reduce blood flow and heat loss.
Fill in the blank: The epidermis is the _______ layer of the skin.
outermost
True or False: The dermis contains free nerve endings sensitive to pain and temperature.
True
What is the purpose of shivering?
Shivering consists of rapid muscle contractions that generate heat through respiration.
What does the liver do in response to low core temperature?
The liver increases its metabolism, such as respiration, which releases heat.
What is the process by which sweat cools the skin?
Sweat is released onto the skin surface from sweat pores. It takes heat energy from the body to evaporate, leaving the skin surface cooler.
This process is essential for thermoregulation.
What happens during vasodilation?
Blood vessels supplying the skin capillaries dilate, allowing more blood flow and increasing heat loss to the environment through radiation.
This process helps cool the organism.
What is the effect of vasoconstriction on blood flow?
Blood vessels supplying the skin capillaries constrict, resulting in less blood flow and reduced heat loss to the environment through radiation.
This process helps the organism retain heat.
What is the normal body temperature in degrees Celsius?
Around 37 degrees.
Maintaining this temperature is crucial for proper physiological function.
What occurs if the thermoregulatory center detects an increase in body temperature?
Sweating, relaxation of hair erector muscles, and vasodilation occur, helping the body return to normal temperature.
Failure to reduce body temperature could lead to hyperthermia.
What happens if there is a decrease in body temperature?
Sweating stops, hair erector muscles contract, vasoconstriction occurs, and shivering increases, aiding in returning to normal temperature.
Failure to increase body temperature could lead to hypothermia.
Why do smaller organisms cool down quicker?
They have a bigger surface area to volume ratio, allowing them to gain or lose heat faster.
This ratio affects heat transfer efficiency.
What is the role of endocrine glands?
They secrete hormones directly into the blood, which dissolve in the blood plasma.
These hormones play critical roles in various bodily functions.
What distinguishes exocrine glands from endocrine glands?
Exocrine glands secrete substances via ducts to the surface, such as sweat, tears, and saliva.
This type of secretion is different from the direct release into the bloodstream.
What are the three main uses of glucose in the bloodstream?
- Broken down in respiration to release energy
- Short-term storage as glycogen in muscle cells or liver
- Long-term storage as fat in adipose tissue
Understanding glucose metabolism is key to managing energy levels.
What hormone is released by the pancreas after a meal when blood glucose levels rise?
Insulin
Insulin helps cells take glucose out of the blood and convert it into glycogen for storage.
What happens to glucose levels when insulin is released?
Blood glucose levels decrease
Insulin facilitates the uptake of glucose by liver and muscle cells.
What is glycogen?
A large, insoluble molecule used for storage
Glycogen is formed from glucose and stored primarily in the liver and muscles.
What hormone is released when blood glucose levels drop?
Glucagon
Glucagon stimulates the conversion of glycogen back into glucose in the liver and muscles.
What are the symptoms of Type 1 diabetes?
- Excreting glucose in urine
- Increased thirst and urination
- Lack of energy and fatigue
- Weight loss
These symptoms occur because glucose cannot enter cells for respiration.
How is Type 1 diabetes often treated?
With injections of insulin or an insulin pump
Insulin therapy is crucial for managing blood glucose levels in Type 1 diabetes.
What is a common method for testing for diabetes?
Using colored test strips to detect glucose in urine or blood glucose sensors
These tests help monitor blood glucose levels.
What characterizes Type 2 diabetes?
The pancreas still makes insulin, but the body stops responding to it
Type 2 diabetes can develop due to obesity and lack of exercise.
What factors can contribute to the onset of Type 2 diabetes?
- Obesity
- Lack of exercise
- Strong genetic tendency
Lifestyle choices play a significant role in the development of Type 2 diabetes.
What are common treatments for Type 2 diabetes?
- Carbohydrate-controlled diet
- Exercise
- Tablets
Lifestyle modifications are crucial in managing Type 2 diabetes.
Define hormones.
Chemicals released into the blood produced in glands
Hormones travel slowly and have long-lasting effects on the body.
What hormone is produced by the adrenal glands and prepares the body for physical activity?
Adrenaline
Adrenaline is also known as epinephrine and is involved in the fight or flight response.
What is the main function of insulin?
Helps control blood glucose
Insulin lowers blood glucose by promoting the conversion of glucose into glycogen in the liver.
What is the primary male sex hormone?
Testosterone
Testosterone is responsible for the development of male secondary sexual characteristics.
What hormone is produced by the ovaries and is the main female sex hormone?
Oestrogen
Oestrogen controls the menstrual cycle and promotes female secondary sexual characteristics.
What hormone supports pregnancy?
Progesterone
Progesterone regulates the menstrual lining of the uterus.
What does ADH stand for?
Antidiuretic Hormone
ADH increases the permeability of the kidney tubes to water.
Which gland is known as the ‘master gland’?
Pituitary gland
The pituitary gland is situated at the base of the brain and regulates various hormonal functions.
What does the pancreas produce besides insulin?
Enzymes such as amylase and lipase
These enzymes aid in the digestion of carbohydrates and fats.
Fill in the blank: The pancreas produces hormones to regulate _______ levels.
blood glucose
True or False: The adrenal glands produce hormones that help control water content in the body.
False
The adrenal glands primarily produce adrenaline and other hormones, while ADH (produced by the pituitary gland) controls water content.
What is the role of adrenaline in the body?
Prepares body for physical activity / fight or flight response
Adrenaline increases heart rate, blood flow to muscles, and energy availability.
What hormone lowers blood glucose by converting it into glycogen for storage?
Insulin
What hormone controls the development of male secondary sexual characteristics?
Testosterone
What hormone controls the menstrual cycle?
Oestrogen
What gland produces oestrogen?
Ovaries
What gland produces testosterone?
Testes
What is the effect of progesterone on the uterus?
Regulates the menstrual lining
What is the primary function of the pancreas?
Regulates blood glucose levels and produces digestive enzymes
Fill in the blank: The adrenal glands produce _______.
Adrenaline
What is FSH?
Female sex hormone produced by the pituitary gland
FSH stands for Follicle-Stimulating Hormone.
What hormone stimulates the ovaries to produce oestrogen?
LH (Luteinizing Hormone)
LH is also produced by the pituitary gland.
What process does LH cause in the ovary?
Maturation of an egg
LH triggers the release of an egg from the ovary.
What is the primary function of adrenaline?
Prepares the body for physical activity - flight or fight
Adrenaline is produced by the adrenal glands.
What happens to glucose in the presence of adrenaline?
Released from the liver
This provides energy for physical activity.
How does adrenaline affect blood flow?
Directed away from the gut and towards the muscles
This enhances physical performance.
What effect does adrenaline have on heart rate?
Increases heart rate
This helps pump more blood to muscles.
What happens to hair when adrenaline is released?
Stands on end
This makes the animal appear larger.
How do pupils react to adrenaline?
Dilate
This allows more light in for better vision.
What change occurs in breathing due to adrenaline?
Becomes faster and deeper
This increases oxygen intake.
What is the main component of the nervous system?
Neurones
Neurones are responsible for transmitting signals.
What is the form of transmission in the nervous system?
Electric impulses
This allows for rapid communication.
What is the speed of transmission in the nervous system?
Fast
This enables quick responses to stimuli.
What is the duration of effect in the nervous system?
Short lived
Effects dissipate quickly after the stimulus.
What is the response of the nervous system?
Localized
Responses are specific to the area stimulated.
What do muscles do in response to the nervous system?
Contract
Muscles are effectors in the nervous system.
What is the primary component of the endocrine system?
Secretory cells in glands
These cells produce hormones.
What is the form of transmission in the endocrine system?
Hormones / chemicals
Hormones are released into the bloodstream.
What is the speed of transmission in the endocrine system?
Slower
Hormonal effects take time to manifest.
What is the duration of effect in the endocrine system?
Longer lasting
Hormonal effects can persist for extended periods.
What is the response of the endocrine system?
Widespread
Hormones affect multiple organs and systems.
What do glands do in the endocrine system?
Secrete hormones into the bloodstream
This is the primary function of endocrine glands.
What do all living organisms need to do in response to their environment?
Detect and respond to changes - stimuli
This is essential for survival.
What does the Central Nervous System (CNS) consist of?
Brain and spinal cord
The role of the CNS is coordination.
What are the two types of matter found in the CNS?
Grey matter and white matter
Grey matter consists mainly of nerve cell bodies, while white matter is mostly myelin sheaths of axons.
What is the role of the Peripheral Nervous System?
Connects all parts of the body to the CNS
It includes sensory and motor neurones.
What are neurones?
Specialised cells that conduct electrical impulses through the body
They play a crucial role in the nervous system.
What are dendrons?
Fine cytoplasmic extensions leading to the cell body
They are part of the structure of a neurone.
What are dendrites?
Finer extensions of the dendrons
Dendrites receive signals from other neurones.
What is the function of the axon?
Carries impulses from the cell body to the effector
It is a crucial part of the neurone’s structure.
What is the neuromuscular junction?
Where the axon meets a muscle
It is essential for muscle contraction.
What is the myelin sheath?
A fatty layer that insulates the axon
It prevents short circuits and speeds up impulses.
What are the three types of neurones?
- Sensory neurones
- Relay neurones
- Motor neurones
Each type has a specific function in the nervous system.
What do sensory neurones do?
Link the receptors to the CNS
They transmit sensory information.
What do relay neurones do?
Link sensory to motor neurones inside the CNS
They help process information.
What do motor neurones link?
Link the CNS to the effector (e.g. muscle)
They facilitate action in response to stimuli.
What is a nerve?
A bundle of many neurones enclosed within a protective sheath
Nerves transmit signals throughout the body.
What is a synapse?
A junction or gap between two neurones, across which chemical signals pass.
Synapses play a crucial role in communication between neurones.
What triggers the release of neurotransmitter molecules at a synapse?
An impulse reaching the synapse at one end of the neurone.
Neurotransmitters are essential for transmitting signals between neurones.
What do neurotransmitter molecules do at the synapse?
They diffuse across the synapse and bind with receptors on the next neurone, triggering another impulse.
This process is vital for the continuation of nerve signals.
What ensures that impulses only travel in one direction across a synapse?
The structure and function of the synapse.
This directional flow is important for the proper functioning of the nervous system.
How can drugs such as heroin affect synapses?
They can alter the function of synapses.
This can lead to changes in mood, perception, and behavior.
What are reflexes?
Fast, automatic responses to certain stimuli that prevent damage to cells and tissues.
Reflexes are critical for survival.
What is a reflex arc?
The route taken by the information in a reflex from the receptor to the effector.
Reflex arcs allow for quick responses without conscious thought.
True or False: Reflex arcs happen without needing to think about them.
True.
This allows for rapid responses to stimuli.
Fill in the blank: A stimulus is detected by a _______ in a sensory organ.
[receptor]
Receptors are specialized cells that detect changes in the environment.
What pathway does an impulse take after being detected by a receptor in a reflex arc?
It is sent along a sensory neurone into the CNS through the dorsal route.
This pathway is essential for processing sensory information.
What connects sensory neurones to relay neurones in the spinal cord?
Synapses where neurotransmitters diffuse across.
This connection allows for communication within the CNS.
What route does the motor neurone take after connecting with relay neurones?
It leaves the spinal cord through the ventral route.
This route is crucial for sending commands to effectors.
What happens at the effector in a reflex response?
The muscle contracts, pulling something away from the harmful stimulus.
This action is a protective mechanism to avoid injury.
What is the function of the conjunctiva?
Lubricates and protects the eye
The conjunctiva is a transparent membrane.
What is the sclera?
The tough outer layer which protects the eye
The sclera provides structural support.
What role does the cornea play in vision?
Refracts most light
The cornea is a transparent part of the thick coating of the eyeball.
What is the purpose of the choroid?
Absorbs light preventing reflection inside the eye
The choroid is the black layer within the eye.
What is the vitreous humour?
Fills the space behind the lens and helps maintain the shape of the eyeball
It is a gel-like substance.
What is the function of the iris?
Regulates how much light enters the eye
The iris is a circular pigmented tissue.
What does the lens do?
Focuses light onto the retina
The lens adjusts to focus on objects at various distances.
Where are light sensitive cells found in the eye?
In the retina
The retina is crucial for converting light into neural signals.
What is the function of the optic nerve?
Sends impulses to the brain
The optic nerve transmits visual information.
What is the role of the aqueous humour?
Fills the space in front of the lens and helps maintain the shape of the eye
It is a clear fluid that also provides nutrients.
What are the two types of light-sensitive cells in the retina?
Cone cells and rod cells
These cells are essential for vision under different lighting conditions.
Fill in the blank: Cone cells only work in _______ conditions.
bright light
Cone cells are responsible for color vision.
What can rod cells detect?
Only black and white
Rod cells do not distinguish colors.
Where are cone cells found in high density?
In the fovea
The fovea is the central region of the retina.
True or False: Rod cells can work in dim light conditions.
True
Rods are more sensitive to light than cones.
Where are rod cells mostly located?
Around the edge of the retina
This distribution helps with peripheral vision.
Why don’t we see colours well at night?
Cones responsible for colour detection only work in bright light
What happens when moving from bright to dim conditions?
Eyes need time to adapt from using cone cells to rod cells
What occurs in the iris and pupil reflex in bright light?
Circular muscles contract and radial muscles relax, causing pupil constriction
What occurs in the iris and pupil reflex in dim light?
Circular muscles relax and radial muscles contract, causing pupil dilation
What is the function of the lens in the human eye?
Changes shape to focus light that enters through the pupil onto the retina
How does light enter the eye and what happens to it?
Light is refracted by the cornea and lens, inverting the image on the retina
What happens to the ciliary muscles when looking at distant objects?
Ciliary muscles relax, allowing suspensory ligaments to pull tight, flattening the lens
What happens to the ciliary muscles when looking at nearby objects?
Ciliary muscles contract, slackening suspensory ligaments, making the lens more rounded
What is short-sightedness caused by?
Cornea/lens refracts light too much or eyeball is too long, focusing images in front of the retina
What is long-sightedness caused by?
Cornea/lens doesn’t refract light enough or eyeball is too short, focusing images behind the retina
What happens to the lens as people get older?
Loses flexibility, making it harder to focus for near viewing, potentially requiring reading glasses
