Responding to the environment Flashcards
Name four different parts of the brain?
Cerebrum
Hypothalamus
Medulla Oblangata
Cerebellum
What is the function of the cerebrum?
This is the area associated with thought, emotions, imagination and reasoning.
What is the function of the medulla oblongata?
This controls the action of smooth muscle in the gut and controls breathing movements and heart rate.
What is the function of the cerebellum?
This controls the coordination of movement and posture.
What is the function of the hypothalamus?
This controls the autonomic nervous system and endocrine glands.
How does the brain act to co-ordinate conscious muscle movement?
Conscious control of movement is achieved by the cerebrum. It contains an area, known as the motor area, which sends electrical impulses to effectors, such as skeletal muscles.
How does the brain act to co-ordinate non-conscious muscle movement?
Non-conscious control of movement is achieved by the cerebellum. The cerebellum receives sensory information from the retina, joints and the inner ear in order to co-ordinate the fine movements associated with tension, posture and manipulation of objects.
Give examples of the function of the cerebrum.
Controls speech
Controls vision
Give examples of the function of the medulla oblongata.
Contains the cardiovascular control centre
Contains the respiratory centre
Give examples of the function of the hypothalamus.
Involved in the secretion of ADH
Associated with thermoregulation.
What is the difference in structure between a synapse and a neuromuscular junction?
Synapse- A junction between two neurones
Neuromuscular junction- A junction between a neurone and a muscle cell.
What ar the similarities in structure between a synapse and an NMJ?
- Contain mitochondria
- Contain neurotransmitters stored in vesicles
- Possess receptors for a neurotransmitter.
What are the differences between a synapse and an NMJ?
- Different shaped membranes (NMJ wavy)
- Different shaped receptors
- Enzymes that breakdown neurotransmitters are stored in different places.
Why do animals have a nervous system?
A nervous system allows for communication between receptors and effectors, so that animals can respond to a changing external environment or internal environment.
What does the nervous system consist of?
The central nervous system and the peripheral nervous system.
What does the PNS split into?
Somatic nervous system (voluntary) and Autonomic nervous system (involuntary)
What does the ANS split into?
Parasympathetic NS and the Sympathetic NS
Where is the CNS found?
Brain and spinal cord
Where is the PNS found?
Sensory neurones and motor neurones
Where is the SNS found?
Sensory neurones and motor neurones connected to skeletal muscle.
Where is the ANS found?
Motor neurones:
- Connected to glands
- Connected to smooth muscle
- Connected to cardiac muscle
What is a ganglion?
It is a collection of neurone cell bodies that lie outside the central nervous system.
What type of interaction does the Para NS and the SNS have?
Antagonistic
What are the similarities in function between a synapse and NMJ?
- Neurotransmitters diffuse across the gap and bind to complementary-shaped receptors.
- Synapses and NMJ contain enzymes that breakdown neurotransmitters.
- Depolarisation occurs on the post-synaptic membrane and the motor end plate.
What are the differences in function between a synapse and NMJ?
- NMJ always release acetylcholine, synapses can release different types of neurotransmitters.
- NMJ results in muscle contraction, synopsis result in propagation of a nerve impulse.
What is innervated by the ANS and SNS?
ANS- Cardiac and smooth muscle
SNS- Skeletal muscle
Ligament
A fibrous tissue that connects one bone to another bone.
Tendon
A fibrous tissue that attaches a muscle to bone
Joint
The point of connection between two or more bones
Synovial fluid
A viscous liquid that lubricates the cartilaginous surfaces of joints.
Cartilage
Pads where bones meet that reduce friction as bones move.
What are the features of a sarcomere?
H-Zone I- band A-zone Z-line M-line
What is the H-zone?
Consists mainly of thick (myosin) filaments.
What is the I band?
Consists of thin (actin) filaments.
What is the A band?
Consists of overlapping thick (myosin) and thin (actin) filaments.
What happens to the parts of a sarcomere during contraction?
A-band- stays the same
I-band decreases in length
H-zone- decrease (disappears)
What is the cell structure of skeletal muscle?
- Multinucleate cells
- Striated cells
- Cells are cylindrical in shape
What is the function of skeletal muscle?
To move bones
What is the structure of smooth muscle?
- Uninucleate cells
- Non-striated cells
- Cells are spindle-shaped
What is the function of smooth muscle?
- Involved in vasodilation and vasoconstriction
- Involved with uterine contractions
- Involved with peristalsis
- Involved with constriction/dilation of the iris
What is the cell structure of cardiac muscles?
- Uninucleate cells
- Striated cells
- Cells are branched with intercalated discs
What is the function of cardiac muscles?
-To pump blood around the body
How does the nervous system influence the fight-orflight response?
Sympathetic pathway becomes more active. Secretes norepinephrine at NMJ.
What is the physiological response to a calm mammal?(8)
- Decreased heart rate
- Weaker contractions
- Decreased breathing rate
- Shallow breathing
- Glycogenesis
- Increased peristalsis
- Increased secretion of enzymes
- Decreased blood flow
What is the physiological response to a stressed mammal?(8)
- Increased heart rate
- Stronger contractions
- Increased breathing rate
- Deep breathing
- Glycogenolysis
- Decreased peristalsis
- Decreased secretion of enzymes
- Increased blood flow
How do the nervous and hormonal systems work together in a fight-or-flight response?
The action of the adrenaline and the autonomic nervous system work together to increase the flow of oxygenated blood to the muscle cells.
This increases the rate of aerobic respiration in muscle fibres.
What effect does the fight-or-flight response have on cardiac muscle?
Heart contracts more rapidly
Heart contracts more forcefully
What effect does the fight-or-flight response have on smooth muscle?
Iris constrict
Airways relax
Skin arterioles constrict
What effect does the fight-or-flight response have on skeletal muscle?
Blood flow to skeletal muscles increases.
What are properties of innate behaviour?
- Genetically-determined, passed directly from parents to offspring via reproduction. (instinctive)
- Fixed and rigid. Patterns of this behaviour are the same in all members of the species. (stereotypical)
What are advantages of innate behaviour?
- Behaviour is performed correctly
- Suit species that have short life-spans
- Lack parental care
- Require a simple nervous system
What are properties of learned behaviour?
- Influenced by genetic factors and the environment. Passed on to offspring by teaching and observing.
- Patterns of this behaviour show some variation between members of the same species. (variable)
- Requires complex NS
What are advantages of learned behaviour?
- Suits species with long life-spans
- Good degree of parental care
- Allows individual to respond to a changing environment.
Innate behaviour: Reflex+ reason
An automatic response to a stimulus.
-This helps to avoid the risk of predation.
Innate behaviour: Taxis +reason
A directional response to a stimulus
-This increases the chances of locating food resources.
Innate behaviour: Kinesis+ reason
A non-directional response to a stimulus
-This helps to keep the organism within favourable environmental conditions.
Innate behaviour: Fixed action pattern(FAP)+reason
A complex set of behaviours that must be completed perfectly without any teaching.
- This reduces inter-specific competition for food resources.
Habituation
This is when an individual learns to ignore a stimulus because repeated exposure results in neither rewards nor punishments.
Imprinting
This is when young animals associate the first individual they see as their parents.
Classical conditioning
This is when an animal learns to associate certain stimuli with a reflex response.
Operant conditioning
This is when an animal learns a set of responses based on positive reinforcement (a reward) or negative reinforcement (a punishment)
Latent learning
This is when an animal explores its surroundings to find out information. The information it learns may become useful in the future.
Insightful learning
This is when an animal thinks independently and uses reasoning to solve a problem. Learning occurs “spontaneously”, which means there was no training involved or any prior trail and error experience.
Unconditioned stimulus
A stimulus that usually causes a reflex response
Neutral stimulus
A stimulus that does not usually illicit a reflex response
Conditioned stimulus
A neutral stimulus that will illicit the same reflex response as an unconditioned stimulus.
Conditioned response
A reflex response to a certain stimulus.
Explain why plants need to respond to their environment in term of the need to avoid predation and abiotic stress.
- Plants carry out a number of responses to their environment to ensure their survival, (e.g avoiding pollutants, deterring herbivores, maximising light absorbance.)
- Plants need to be sensitive to a range of stimuli
- Multicellular-cell signalling
- Have hormones, chemical messengers that have target sites.(growth factors)
How can hormones move around the plant?
- Active transport
- Diffusion
- Mass flow in the xylem and phloem.
Tropism
A directional growth response in which the direction of the response is determined by the direction of the external stimulus.
Name examples of different tropisms
Phototropism
Chemotropism
Geotropism
Thigmotropism
What does Auxin do?
- Involved in cell elongation
- Inhibits leaf abscission
- Inhibits growth of side shoots
What are the commercial uses of Auxins?
- Taking cuttings: root powder, which encourages root formation
- Seedless fruit
- Herbicides
What does gibberellins do?
Seed germination
Stem growth
What are the commercial uses of gibberellins?
Fruit production
Brewing
Sugar production
Plant breeding
What do cytokinins do?
Cell division
What are the commercial uses of cytokinins?
Prevents yellowing of cut lettuce leaves
Tissue cultures-helps promote root and shoot growth by cell division
What does ethene do?
Fruit ripening
What are the commercial uses of ethene?
Preventing fruit ripening
What does abscisic acid do?
Inhibits seed germination
Inhibits growth
Causes stomata closure when water availability is low
What is the commercial use of abscisic acid?
Seed storage
How does Auxin cause cell elongation?
- Activates ATPase
- ATPase pumps H+ into cellulose cell wall.
- The build of H+ decreases the pH of the cell wall to the optimum pH of the enzyme Expanase.
- The enzyme breaks down the cell wall.
- More water moves into the cell and becomes turgid.
Outline the role of hormones in leaf loss in deciduous plants.
- Cytokinins in the leaf act as the nutrient sink in the lead preventing senescence.
- If cytokinin levels in the leaf drop then nutrients levels in the leaf drop.
- decrease in cytokinins= senescence= L auxins= H ethene
