Co-ordination and control Flashcards
Name the two control systems in place in mammals
The nervous system and the endocrine system
Definition of a nervous system
a control system comprising neurons connected in networks that control essential sensory, motor and complex functions of an organism
What is the CNS tissue made up of?
Neurones and glial cells
Briefly describe neurones
Electrically active cells capable of transmitting information. Link to other neurones or muscle cells through junctions called synapses by releasing chemical neurotransmitters.
Briefly describe glial cells
Supportive cells of various types. Provide mechanical support but also maintain an optimal physiochemical environment. Some types produce myelin a lipid material, which is white in appearance, and helps to insulate the axons of neurones.
What is the central nervous system made up of?
The brain and the spinal chord
What is the peripheral nervous system made up of?
Cranial nerves - 12 pairs in humans Spinal nerves - 31 pairs in humans
What information goes towards the CNS?
Sensory, from a stimulus
What information goes away from the CNS?
Motor, resulting in a response
What are some of the integrated functions of the human nervous system?
intellect, consciousness, emotions, motivation, association, memory, language
What the subdivisions of the nervous system?
What’s another word for the autonomic system?
Visceral
The sensory division of the PNS is also known as…
afferent
The motor division of the PNS is also known as the…
Efferent system
What do the general somatic afferent nerves sense?
touch, pain, vibration, temperature, pressure, proprioception
What do the special somatic afferent nerves sense?
hearing, vision, balance
What do the general visceral afferent nerves sense?
stretch, pain, temperature, chemical changes & visceral irritation, nausea & hunger
What do the special visceral afferent nerves sense?
smell & taste
What do general somatic efferent nerves have control over?
motor innervation of all skeletal muscles
What do general visceral nerves have control over?
motor innervation of smooth & cardiac muscles, glands
Definition of the autonomic nervous system
A nervous control system that functions largely below the level of consciousness and controls visceral functions
What does the autonomic nervous system include?
Involves nerves which supply involuntary structures (eg. heart, lungs, GIT, smooth muscle, glands, pupil) & is a purely motor system
What is the anatomical difference between somatic and autonomic divisions of the nervous system?
The first is the somatic division and the second is the autonomic division
What’s the difference between grey matter and white matter?
White matter is mainly myelinated axons.
Grey matter is mainly cell bodies
What does the endocrine system do?
Cell communication
Controls all major body processes
Reproduction, homeostasis, regulating behaviour and mood, growth, inflammatory response
Describe some of the features of endocrine glands
They contain tissue capable of releasing one or more hormones directly into blood
Endocrine tissues/glands have a rich vascular supply
They are widely distributed around the body
There are over ten major and eight minor endocrine glands
What are the three arrangements of endocrine tissue?
- Endocrine organs devoted to hormone synthesis eg thyroid
- Cluster of cells within an organ eg. Islets of Langerhans (pancreas)
- Individual cells scattered diffusely throughout an organ, eg. GI tract
Name the 8 minor endocrine glands
Pineal Gland, Placenta, Kidneys, Stomach, Duodenum, Liver, Skin, Heart
Name the 10 major endocrine glands and one hormone they release
Compare and contrast nervous and hormonal control
Hormone signals tend to be much more diffuse
Hormone signals tend to be more slow to act
Hormones are capable of exerting very long lasting and sometimes permanent effects on their target
What does it mean that endocrine glands form an integrated system?
Several glands are able to act in concert (e.g. pituitary, adrenal and pancreas in glucose homeostasis)
What’s special about the pituitary gland?
The pituitary is like two glands in one. There are two lobes- the posterior and the anterior lobes.
It’s also known as the master gland
Describe the posterior pituitary lobe
Neural tissue that comprises hypothalamic axons & nerve terminals
DIRECT CONTROL
Neurohypophyseal hormones: Oxytocin, arginine-vasopressin (ADH)
Descibe the anterior pituitary lobe
A true gland that receives hypothalamic releasing hormones via portal blood supply.
INDIRECT CONTROL
Adenohypophyseal hormones:
(i) Hormones with tropic action: Follicle stimulating hormone (FSH), Luteinising hormone (LH), Adrenocorticotrophic hormone (ACTH), Thyroid stimulating hormone (TSH)
(ii) Other hormones:Growth hormone, prolactin
What does neuroendocrine control refer to?
It refers to the hypothalamus- pituitary control of some endocrine glands, specifically: the thyroid gland, the adrenal gland, and the gonads (ovary/testis)
What is neuroendocrinology?
Branch of endocrinology specifically dealing with the hypothalamic control of the pituitary
Includes tripartite axis control (thyroid, adrenal & gonadal functions)
Balance between increased output (forward drive) & hormone negative feedback is key
What are some of the causes of endocrine disorders?
Hormone deficiency: Destruction of gland, Extraglandular disorder, Defect in biosynthesis
Hormone excess: Tumours of endocrine gland, Ectopic hormone production, Overstimulation (hyperplasia), Exogenous hormone
Hormone resistance: Receptor defects
