The Nervous System 1 - Human Physiology 1 PDF

The Nervous System 1 Human Physiology 1 Module Plan Week Content % Detail Structural Organisation/ Levels Organisation of the Body 5 1...

The Nervous System 1 Human Physiology 1 Module Plan Week Content % Detail Structural Organisation/ Levels Organisation of the Body 5 1 Functional Characteristics of Life Outline of major organs and primary functions of the Overview of Organ Systems 5 systems of the body. Homeostatic Principles and Components 2 Homeostasis 5 Negative & Positive Feedback Mechanisms Examples of homeostatic control in the human body. The Central Nervous System - Structural Organisation of the Brain - Spinal Cord Tracts 3 Nervous System: Organisation 5 - Cranial & Spinal Nerves The Autonomic Nervous System - Divisions & Functions Neurons Neurotransmitters Nervous System: Functional 4 10 Components Synapses Conduction of Nerve Impulses Structure of Skin & Underlying Tissue 5 Integumentary System 10 Functions Accessory Skin Structures Classification of Hormones Endocrine System: Hormone 5 Interaction with Target Tissues Mechanisms of Hormone Action 6 Hypothalamic Control of the Pituitary Gland Endocrine System: Endocrine Glands & Endocrine Glands - Adrenal, Thyroid, Parathyroid, Pancreas, 10 Hormones Pineal, Gonads, Placenta Disorders associated with hypersecretion and hyposecretion of hormones The Nervous System 1.Functions 2.Central Nervous System 3.Peripheral Nervous System 4.Structure The Nervous System Functions of the Nervous System 1. Nervous system and endocrine system are the chief control centres in maintaining body homeostasis. 2. Nervous system uses electrical signals (nerve impulses) which produce immediate (but short-lived) responses; endocrine system uses chemical signals (hormones) that produce slower (but long lasting) responses. The Nervous System Functions of the Nervous System 3. Nervous system has 3 major functions: Sensory input –sensory or afferent neurons detect internal or external changes ( stimuli ) and send the message to the brain or spinal cord. Integration–interneurons in the brain or spinal cord process and interpret the message from the sensory neurons, and relay the massage back to body parts. Motor output –motor or efferent neurons receive the message from interneuron and produce a response at the effect or organ (a muscle or a gland). The Nervous System  Parts of the Nervous system Central nervous system (CNS): Brain Spinal Cord Peripheral nervous system (PNS): Somatic nervous system Autonomic nervous system Parts of the Nervous system Brain CNS - Brain and Spinal cord Protected by bone Wrapped in 3 layers of connective tissue = meninges Layers may have a space between them filled with cerebrospinal fluid which protects (shock absorber) and exchanges nutrients and waste Cerebrospinal Fluid Circulates continuously Function: Serves as shock absorber to protect brain and spinal cord Carries nutrients to parts of brain and spinal cord Helps remove metabolic products & wastes Brain Brain Cerebellum – coordination of movement and aspects of motor learning Cerebrum – conscious activity including perception, emotion, thought, and planning Thalamus – Brain’s switchboard – filters and then relays information to various brain regions Medulla – vital reflexes as heart beat and respiration  Brain Brainstem – medulla, pons, and midbrain (involuntary responses) and relays information from spine to upper brain Hypothalamus– involved in regulating activities internal organs, monitoring information from the autonomic nervous system, controlling the pituitary gland and its hormones, and regulating sleep and Brain Brain Spinal Cord Links communication between the brain and the body Spinal nerves branch out from the spinal cord connecting brain to body Reflexes = quick, automatic responses to stimuli are processed directly in the spinal cord Nervous System Overview https://www.youtube.com/watch?v=jmD0LBdAvlE Peripheral Nervous System Part of Nervous System outside of CNS It consists mainly of the nerves that extend from the brain and spinal cord They link all the parts of the body by carrying impulses from sensory receptors to the CNS and from the CNS to the muscles Cranial nerves: (12 pairs) to and from the brain Spinal nerves: (31 pairs) to and from the spinal cord Peripheral Nervous System Consists of nerves and associated cells that are not part of the brain or spinal cord Receives information from the environment and relays commands from the CNS to organs and glands Divided into two parts: Somatic Automatic Peripheral Nervous System Peripheral Nervous System Somatic Nervous System Part of motor division that regulates activities that are under conscious control (movement of skeletal muscles) It contains both afferent nerves (which send information to the brain and spinal cord), made of sensory neurons that inform the central nervous system about our five senses; and efferent nerves (which send information from the brain), which contain motor neurons responsible for voluntary movements, such as walking or lifting an object. Peripheral Nervous System Autonomic Nervous System (involuntary) Regulates bodies involuntary responses Relays information to internal organs Two divisions 1. Sympathetic nervous system – in times of stress Emergency response Fight or flight 2. Parasympathetic nervous system – when body is at rest or with normal functions Normal everyday conditions Autonomic Nervous System (involuntary) The sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. The parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions. The effects of the parasympathetic nervous system can be summarized by the phrase 'rest and digest'. Niall O’ Mahony Classes of Neurons Afferent neurons: Known as sensory neurons, transmit sensory signals to the CNS from receptors in the body. Efferent neurons: Transmit signals from the CNS to effectors in the body such as muscles and glands. Interneurons: Form complex networks within the CNS to integrate the information received from afferent neurons and to direct the function of the body through efferent neurons. Muscle Stretch Reflex The muscle stretch reflex is a crucial nervous system response that protects muscles from rapid stretching. The reflex involves afferent and efferent parts, both of which are necessary for it to work. This reflex is the reason for the knee-jerk reaction when the doctor taps just below the kneecap. https://youtu.be/Ya-3XHBWDqs?feature=shared Nervous Tissue The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia. 1. Neurons Excitable nerve cells Transmit electrical signals 2. Neuroglia or just glia Means “nerve glue” Supporting Cells Neurons Also known as nerve cells, communicate by transmitting electrochemical signals. The cell body is the round part of a neuron that contains the nucleus and mitochondria. Dendrites extend from the cell body to pick up stimuli from the environment, neurons, or sensory receptor cells. Axons extend from the cell body to send signals onward to other neurons or effector cells in the body. Neurons Anatomy of the Neuron https://www.youtube.com/watch?v=ob5U8zPbAX4 Neuroglia Also known as glial cells, act as the “helper” cells of the nervous system. Each neuron in the body is surrounded by anywhere from 6 to 60 neuroglia that protect, feed, and insulate the neuron. Neuroglia Supporting cells = neuroglia (“nerve glue”) or glial cells CNS Astrocytes Oligodendrocytes Microglia Ependymal cells PNS Schwann cells Satellite cells https://www.youtube.com/watch?v=AwES6R1_9PM Neuroglia (CNS glial cells) Astrocytes Star shaped; the most numerous Involved in metabolism & synapse formation Microglia Contains Phagocytes are cells that protect the body by ingesting (phagocytosing) harmful foreign particles, bacteria, and dead or dying cells Ependymal cells Line the cavities of CNS and spinal cord; cilia Oligodendrocytes Produce myelin sheaths in CNS Neuroglia (PNS glial cells) Satellite cells Surround neuron cell body Schwann cells Form myelin in PNS https://www.khanacademy.org/science/health-and- medicine/nervous-system-and-sensory-infor/neural-cells- and-neurotransmitters/v/introduction-to-neural-cell-types Nerves Neurons bundle together to form nerves Some nerves may be only a few neurons, and others may be hundreds or thousands The myelin sheath may insulate axons by surrounding it There may be some gaps in the myelin sheath called nodes of ranvier Impulses jump from one node to the next, increasing the speed impulses travel Kahoot Quiz https://create.kahoot.it/details/ 2b87701e-8b14-45ca-b37e- 863cf09ecd9e Parts of the Nervous System