Ectodermal derivatives Integumentary system The skin has a double origin.
Neuroscience of sex differences The adult human brain weighs on average about 1.
Each hemisphere is divided into four main lobes although Terminologia Anatomica and Terminologia Neuroanatomica also include a limbic lobe and treat the insular cortex as a lobe.
The brainstem includes the midbrain, the ponsand the medulla oblongata.
Behind the brainstem is the cerebellum Latin: The membranes are the tough dura mater ; the middle arachnoid mater and the more delicate inner pia mater.
Between the arachnoid mater and the pia mater is the subarachnoid spacewhich contains the cerebrospinal fluid.
Dashed areas shown are commonly left hemisphere dominant Main articles: Cerebrum and Cerebral cortex Major gyri and sulci on the lateral surface of the cortex Lobes of the brain The cerebrum is the largest part of the human brain, and is divided into nearly symmetrical left and right hemispheres by a deep groove, the longitudinal fissure.
It is 2 to 4 millimetres 0. The largest part of the cerebral cortex is the neocortexwhich has six neuronal layers. The rest of the cortex is of allocortexwhich has three or four layers.
The hemispheres are connected by five commissures that span the longitudinal fissurethe largest of these is the corpus callosum. There are many small variations in the secondary and tertiary folds. These areas are distinctly different when seen under a microscope.
The primary sensory areas receive signals from the sensory nerves and tracts by way of relay nuclei in the thalamus. Primary sensory areas include the visual cortex of the occipital lobethe auditory cortex in parts of the temporal lobe and insular cortexand the somatosensory cortex in the parietal lobe.
The remaining parts of the cortex, are called the association areas. These areas receive input from the sensory areas and lower parts of the brain and are involved in the complex cognitive processes of perceptionthoughtand decision-making.
The temporal lobe controls auditory and visual memorieslanguageand some hearing and speech. Below the corpus callosum is the septum pelluciduma membrane that separates the lateral ventricles.
Beneath the lateral ventricles is the thalamus and to the front and below this is the hypothalamus. The hypothalamus leads on to the pituitary gland. At the back of the thalamus is the brainstem.
Below and in front of the striatum are a number of basal forebrain structures. These include the nucleus accumbensnucleus basalisdiagonal band of Brocasubstantia innominataand the medial septal nucleus.
These structures are important in producing the neurotransmitteracetylcholinewhich is then distributed widely throughout the brain.
The basal forebrain, in particular the nucleus basalis, is considered to be the major cholinergic output of the central nervous system to the striatum and neocortex. Cerebellum Human brain viewed from below, showing cerebellum and brainstem The cerebellum is divided into an anterior lobea posterior lobeand the flocculonodular lobe.
Brainstem The brainstem lies beneath the cerebrum and consists of the midbrainpons and medulla. It lies in the back part of the skullresting on the part of the base known as the clivusand ends at the foramen magnuma large opening in the occipital bone.
The brainstem continues below this as the spinal cord protected by the vertebral column. Ten of the twelve pairs of cranial nerves [a] emerge directly from the brainstem. Types of neuron include interneuronspyramidal cells including Betz cellsmotor neurons upper and lower motor neuronsand cerebellar Purkinje cells.
Betz cells are the largest cells by size of cell body in the nervous system. Astrocytes are the largest of the glial cells. They are stellate cells with many processes radiating from their cell bodies.
Some of these processes end as perivascular end-feet on capillary walls. Myelin basic proteinand the transcription factor, OLIG2 are expressed in oligodendrocytes.The gray substance contains primitive stem cells, many of which differentiate into pfmlures.com neuroblast becomes a neuron, or a mature nerve cell, with numerous short branching processes, the dendrites, and with a single long process, the pfmlures.com white substance lacks neuroblasts but contains closely packed axons, many with fatty sheaths that produce the whitish appearance.
Feb 15, · 1. What do holocrine glands secrete? 2. Each hair grows in an oblique epithelial tube called a ___. 3. Dead keratinized cells form from the sratum ___ of the pfmlures.com: Resolved.
Jul 08, · The ciliated epithelium of your airway forms a mucociliary 18 apr in this tissue the epithelial cells bear at their free ends thin elongated cytoplasmic processes called cilia (sing cilium). Ovarian cancer is a cancer that forms in or on an ovary.
It results in abnormal cells that have the ability to invade or spread to other parts of the body. When this process begins, there may be no or only vague symptoms. Symptoms become more noticeable as the cancer progresses. A hair grows in a diagonal epithelial tube called a ____. 3. Coarse, pigmented hair is called ____, whereas most of the body hair of women and children is called ____.
A hair grows in a diagonal epithelial tube called a _follicle___. 3. Coarse, pigmented hair is called __terminal hair__, whereas most of the body hair of women and children is called __vellus__%(1).