Nerves and Hormones Summary

Receptors and Stimuli CNS Stimulus Receptor Effector Response Nervous System Impulse is electrical Nerve Structure Fast, local response Receptor Coordinating Centre Effector Response Light Sound Position Touch Pressure Chemical Temperature Synaptic Gap

Reflex Actions Reflex Arc Takes 1/30th of a second

Controlled Internal Conditions Homeostasis So enzymes operate at the optimum speed Enzymes Temperature Concentration Glucose Levels Water Salt

Hormones Glands Long-term response Bloodstream Slow, widespread response Pituitory Adrenal Gonads Thyroid Pancreas Master Gland Growth Hormone Adrenaline Hormone Testosterone Oestrogen Thyroxine Insulin Lack of; Type 1 diabetes Too much of; Type 2 diabetes

Menstrual Cycle FSH Oestrogen LH Progesterone Causes egg to mature in ovary Stimulates ovaries to release oestrogen Pituitory Gland Stops FSH production Thickens blood Stimulates pituitory gland to release LH Causes ovulation Maintains lining of uterus Inhibits production of LH and FSH

Hormone Use in Fertility Oral contraceptive pill Synthetic oestrogen and progesterone Inhibits FSH so follicle doesn't mature In vitro fertilisation Extra FSH Removal of eggs Fertilisation in laboratory Return embryos to uterus Sometimes multiple babies

Tropism Auxin Plant cell growth Changes elasticity of cells Diffuses Roots Negatively Phototropic Positively Geotropic Stem tips Negatively Geotropic Positively Phototropic

Uses of Plant Hormones Herbicides Growth Promoters

Reflex Action; An action you can't control- it happens without you thinking about it. Very quick.

Chemical messages released by glands.

Menstrual cycle; Oviduct (fallopian tube), ovaries, cervix, uterus, follicles, eggs, ovulation, 28 days, Day 0-7, lining breaks down

Tropism- A growth movement of a plant in response to external stimulus, direction of stimulus determines direction of growth

The CNS- Brain and Spinal Cord

Stimuli- Change in the surroundings

Receptors- cell detecting change

Effector- Organ that responds

Response- How body reacts to stimulus

Light- Eye

Sound- Ear

Position-Ear

Touch- Skin

Pressure- Skin

Chemical- Tongue, Nose, Blood Vessels. Blood vessels affect the breathing rate by measuring pH levels 

Temperature - In body, blood vessels. Outside body, skin.

Receptor -> along Sensory Neuron -> Relay neuron and CNS -> Motor Neuron -> Effector

Nervous System;  Brain, Spinal Cord, Nerves, Sensory/Relay/Motor Neurons 

Synapse- Where two neurons connect. Synaptic Gap- The gap between dendrites of one and axonal terminal of the other. Neurotransmitters diffuse across gap causing transmission of impulse

Reflex Arc-  Shortest route, bypassing brain, path taken by impulse in reflex action

Controls all other glands in body

Growth Hormone; controls growth in body

Adrenaline; blood sugar surge, fight/flight response, faster heart beat, energy boost

Gonads- Sex Glands

Testosterone; Puberty and fertility, sperm production, sexual development

Oestrogen; Control puberty and fertility, controls menstrual cycle, sexual development

Thyroxine; controls metabolic rate inside cells

Insulin; causes body to store extra sugar as glycogen for use between meals

Homeostasis; Keeping the conditions the same

Ovulation - Day 14

Extra FSH- more eggs mature

Fertilisation in laboratory- 2-3 days 

Auxin- Plant hormone responsible for controlling direction of growth in roots and stems. Made at tip of stem and roots.

If covered- auxin evenly distributed, even growth. If sunlight on one side- auxin accumulates on shady side and the plant bends. The bit underneath is then shady so it repeats and shoot bends upwards.

Herbicides- spray auxin on weed and it grows too quickly and dies

Growth Promoters- use cuttings to clone plants, rooting powder contains auxin so that cutting develops roots

Nerves and Hormones

Annotations