biology revision for 25th Flashcards
describe the capillary network
1 cell thick
network structure
required for the diffusion of oxygen, nutrients and waste
describe the structure of veins
thin, elastic muscular walls. large lumen
contains valves
what is the function of veins?
carries blood back towards the heart
describre the structure of artery’s
thick, elastic muscular walls, small lumen
no valves.
what is the function of Artery’s
carrys blood away from the heart
what are erthrocytes
red blood cells
leukocytes
white blood cells
how much of the blood is made up of plasma
55%
what are the main components of blood?
red blood cells
white blood cells
platelets
plasma
how much of the blood is made up of white blood cells and platlets?
less than 1%
how much of the blood is made up of red blood cells
45%
what is the function of white blood cells
fight infection, desease and forign bodies
what is the function of red blood cells
carry oxygen and food around the body
what are the functions of the lymphatic system
drain excess fluid
aid with fat digestion
transport of materials
immunity
what are the lymphatic structures
Lymph Fluid Lymph Nodes Lymphatic vessels Lymphocytes Thymus Spleen
what is endocrinology
the study of hormones
what are the endocrine system structures
Hypothalamus Pituitary Pancreas Adrenal Ovaries Testes Thyroid Para-thyroid
what are the requirments of receptors on the cell surface?
In order for a hormone to create a response in a cell, that cell must have specific receptors on its surface for that particular hormone
what is homeostasis
The maintenance of a constant internal environment
what processes are controlled by homeostasis
Glucose regulation Thermoregulation Osmoregulation Blood pressure Reproductive cycles
what is glucose regulation
Maintaining a consistent level of sugar in the blood.
what are the two jobs of the pancrease
exocrine and endocrine
what is exocrine?
secretes digestive juices into the digestive tract
what is endocrine
makes hormones to control blood
sugar levels
what are affrent nerves
sensory nerves
what are effrent nerves
motor nerves
what is the function of the Sclera
in the eye
A white fibrous layer that maintains the shape of the eye
what is the function of the Rods
in the eye
Sensitive to low light and used for black and white vision
what is the function of the Lens
in the eye
Changes shape to focus light rays onto the retina
what is the function of the Retina
in the eye
Innermost layer of the eye, contains photoreceptor cells
what is the function of the Optic Nerve
in the eye
Transmits images from the eye to the brain
what is the function of the Cornea
in the eye
The first part of the eye to be hit by light rays
what is the function of the Cones
in the eye
Sensitive to bright light and used for colour vision
what is the function of the Iris
in the eye
A circular muscle that controls the size of the pupil
what is the function of the Pupil
in the eye
A hole in the centre of the eye that light rays travel through
what is the function of the Ciliary Muscle
in the eye
Used to control the shape of the lens
what does the forbrain contain
ceribral cortex, thalamus, hypothalumus and the limbic system
what does the thalamus control?
Pain receptors, touch, temperature sensation.
Movement (locomotion).
what does the hypothalamus control
The function of the autonomic nervous system.
Intellectual and functional signals.
Temperature regulation and osmoregulation
what does the limbatic system control
Long term memory.
Emotional behaviour.
Olfactory senses (smell
how does ecolocation work
Animals emit sound waves that are detected when they bounce off objects
Sound waves travel faster through water than air
Used by mammals (cetacaeans and bats)
what is ecolocation used for?
Can detect location, size and direction of prey movement
Smaller object = fewer waves returned
Moving away = lower pitch
Can determine vertical position using collection of folds in ears
how are the soundwaves for ecolocation detected in dolphims?
Sound waves are directed using the melon
Lower jaw detects returning waves and is connected to the ear
