Plant and animal responses Flashcards
Types of stimuli (plants)
Higher temps- thicker waxy cuticle
Wind- more lignified vascualr tissue
Herbivores:
* Tannins -toxic to mammals + stops pathogens coming to roots
* Alkaloids- (aa) Bitter taste to animals
* Pheromones- Affects behaviour and physiology of another
Tropisms
Directional growth responses of plants
Can be positive (towards) or negative (away)
Phototropism
(+) Growth towards the light
Geotropism
(+) Roots growing towards the pull of gravity
Chemotropism
(+) (when pollen lands on a flower) the pollen tubules growing towards chemicals produced by the ovary so it can be fertilised.
Thigmotropism
(+) shoots of climbing plant/ growth towards touch
Nastic responses
Non-directional responses to external stimuli
Example: thigmonasty- folding of leaves
What controls plant responses?
Hormones
Not produced in endocrine glands but a variety of tissues in the plant.
How are hormones transported around the plant?
- Active transport
- Diffusion
- Mass flow in phloem sap
Auxin
Plant hormone (IAA)
* Promotes cell elongation
* inhibit growth of side shoots
* inhibit leaf abscission (leaf fall)
Apical dominance
Abscisic acid
Plant hormone
- Inhibits seed germination and growth
- causes stomatal closure when water availability is low
Cytokinins
PLANT HORMONE
- Promote cell division
- Delay leaf senescence (aging in plants)
- Overcome apical dominance
- Promote cell expansion
Gibberellins
Promote seed germination and growth of stems
Ethene
PLANT HORMONE
Promotes fruit ripening
FUNCTIONS
Cerebrum
brain
- Conscious thought
- Ability to override some reflexes
- Emotional responses
- Intelligence (reasoning and judgement)
FUNCTIONS
Cerebral cortex- Sensory areas
brain
Recieve impulses indirectly from receptor
FUNCTIONS
Cerebral cortex- Motor areas
brain
Motor areas on left side of brain control muscle movement on the right side of the body and vice versa
FUNCTIONS
Cerebral cortex- Association areas
brain
Compares input w/ prev. experience in order to interpret meaning and appropriate response.
Hypothalamus
Controls body’s homeostatic mechanisms via its own sensory receptors
* osmoregulation
* thermoregulation
Pituitary gland-Posterior
Releases hormones made in the hypothalamus
* ADH
* Oxytocin (childbirth)
Pituitary gland- Anterior
** Releases pituitary gland’s own hormones** (made in response to hypothalamus releasing factors).
Regulates:
* stress
* lactation
* growth
* reproduction
Medulla Oblongata
Location of regulatory centres for vital processes
* Cardiac centre
* Vasomotor centre (blood pressure)
* Respiratory centre
FUNCTIONS
Medulla Oblongata
Controls non-skeletal (involuntary) muscle to regulate:
* heart rate
* blood pressure
* breathing rate & depth
Cerebellum
SENSORY INFO
Processes sensory info:
* joints
* muscle splindle fibre
* inner ear
* retina
Cerebellum
MOTOR RESPONSES
Coordinates motor responses (unconsciously):
* staying balanced & upright
* Operation of antagonistic muscles
* muscle tension for instrument use
Corpus Callosum
Connects both sides of the brain
-ensures both sides can communicate w/ each other
What is a reflex action?
Responses to changes in the environment that don’t involve the brain to coordinate the movement
* Short and rapid
* Only 3 neurones most of the time: sensory»_space;> relay»> motor
Why do we need reflexes?
- To get out of danger
- avoid damage to part of the body
- maintain balance
What is the blinking reflex?
Temporary closure of eyelids to protect the eyes.
A cranial reflex (passes through part of the brain) but doesn’t require thought.
Reflex arc (effector and receptor in the same place)
What stimulates blinking?
- Lound sounds
- Sudden movements close to the eye
- sudden bright light (optical reflex)
- foreign object touching eye (corneal reflex)
