Chapter 13 Other Animal Responses Flashcards
What is fight or flight? What detects it?
The physiological response initiated when a threat is perceived, aims to increase success of survival by fleeing or fighting
The autonomic nervous system, coordinated by the hypothalamus
What is the neuronal pathway initiated with fight or flight?
The hypothalamus activates the sympathetic nervous system
The sympathetic sends impulses to activate glands and smooth muscles
The sympathies sends impulses to activate the adrenal medulla, which will go on to secrete noradrenaline and adrenaline
What is the hormonal pathway stimulated by fight or flight?
The hypothalamus releases CRF to activate the adrenal-cortical system
The pituitary then releases ACTH into the blood to reach the adrenal cortex, which then secretes 30 hormones for response
What does adrenaline do? What does noradrenaline do?
Adrenaline- glycogenolysis, divert blood flow to muscles, increase heart rate
Noradrenaline- widen pupils, divert blood flow away from digestive system, increases air passage, increase heart rate
What is the action of adrenaline (simpleish)?
As a hydrophilic hormone, it will bind to its complimentary glycoprotein receptor in the cell surface membrane, as it cannot pass through the phospholipid bilayer
Associated G-protein activates the enzyme adenylyl cyclase, which catalyses the conversion of ATP into cAMP which are secondary messengers
cAMP activate protein kinases, which can phosphorylate and activate enzymes that carry out the desired response e.g glycogenoysis
How can the same hormone have different responses in difference cells? Give an example
E.g acetylcholine- nerve impulses Vs decreases heart rate
Could produce different secondary messengers, different protein kinases activated, difference enzymes activated
Or different type of receptors to the same hormone to different responses
What is the cascade effect with hormones?
One hormone will produce multiple cAMP which will each activate many PKA and each will activate/phosphorylate many enzymes
Exponential increase of activity from one hormone by having multiple messengers
What is the pathway in which heart rate increases?
Sympathetic neurones secrete noradrenaline which travels through the accelerons nerve to the SAN, and upon binding to complimentary receptors, causes an increase in heart rate
What is the pathway by which heart rate decreases?
Parasympathetic neurones secrete acetylcholine which travels through the vagus nerve to the SAN, and upon binding, causes a decrease in heart rate
What types of receptors are found in the heart and why?
Chemoreceptors- blood pH changing, if pH decreases, need to increase heart rate to exhale CO2 more as too acidic via the sympathetic nervous system
Baroreceptors- changes in pressure, alter heart rate with the para/sympathetic nervous system
How do hormones changes heart rate compared to the nervous system?
Similarities, but hormones can directly interact with the SAN changing frequency of depolarisation, but nervous system needs to go through with nerves to SAN and synapse
What is the organisation of the nervous system?
CNS- brain and spinal cord ——————— PNS- sensory and motor neurones
The PNS is divided into the somatic nervous system- conscious controls to skeletal muscles, heavily myelinated
And Autonomic- subconscious control, muscles and glands
The autonomic is further split into the Sympathetic- fight or flight noradrenaline, and Parasympathetic- relaxing, acetylcholine
General sympathetic increases response, parasympathetic decreases response
What are the main parts of the brain?
Cerebrum
Cerebellum
Pituitary gland
Hypothalamus
Medulla
What is the function of the cerebrum?
Receives sensory information and compares it to stored information, sends impulses along motor neurones for response
Coordinates all voluntary responses
So learning, memory, personality, conscious thought
How is the cerebrum adapted for its function?
Highly convoluted, meaning it has a high surface area for increased capacity
Smaller size to ensure balance
